Chemistry - Prince Edward Island · Curriculum (1998). Chemistry 521A includes the following...

SAtlantic Canada

Science Curriculum

Chemistry621A

CU

RR

ICU

LUM

Chemistry

Prince Edward Island

Department of Education

Implemented September 2006

ATLANTIC CANADA SCIENCE CURRICULUM: PRINCE EDWARD ISLAND CHEMISTRY 621A iii

ACKNOWLEDGEMENTS

The Atlantic Provinces Education Foundation and the P.E.I.Department of Education expresses its indebtedness to members ofthe local and regional chemistry committees for their professionalexpertise and insights in developing this regional Chemistry 621Acurriculum guide. In addition, pilot teachers and others whocontributed comments and suggestions are to be commended fortheir commitment to developing exemplary science programs.

Prince Edward Island Chemistry Curriculum Committee membersand pilot teachers include:

Charlottetown Rural High School Kim McBurney

Rosanne Ostridge

Lori Hudson

Colonel Gray Senior High School Lee Ann Mitchell

Kinkora Regional High School Brendan Kelly

Montague Regional High School Philip MacDonald

Three Oaks Senior High School Dia-Lynn Keough

Kathy McDonald

Department of Education Jonathan Hayes

The Prince Edward Island Department of Education would also liketo thank all individuals who have contributed to the development ofthe Chemistry 621A curriculum guide.

Acknowledgements

ATLANTIC CANADA SCIENCE CURRICULUM: PRINCE EDWARD ISLAND CHEMISTRY 621A v

CONTENTS

ContentsForeword

Introduction

Program Designand Components

..................................................................................................... 1

Background .................................................................................. 3Aim .............................................................................................. 3Learning and Teaching Science .................................................... 5

Communicating in Science ......................................................... 6The Three Processes of Scientific Literacy ................................... 7Meeting the Needs of All Learners .............................................. 8Assessment and Evaluation .......................................................... 9Assessment Techniques ................................................................ 9

Overview ....................................................................................13Essential Graduation Learnings .................................................14General Curriculum Outcomes .................................................15Key-Stage Curriculum Outcomes .............................................15Specific Curriculum Outcomes .................................................15Attitude Outcomes ....................................................................16Curriculum Guide Organization ..............................................19Unit Organization .....................................................................19The Four-Column Spread .........................................................20

CurriculumOutcomesFramework

Introduction ..............................................................................22Focus and Context .....................................................................22Science Curriculum Links .........................................................22Curriculum Outcomes ..............................................................23




Thermochemistry

From Solutions toKinetics toEquilibrium

Acids and Bases

Electrochemistry

Chemistry 621A Units

Appendix A Instructional Planning ............................................................ 101

ATLANTIC CANADA SCIENCE CURRICULUM: PRINCE EDWARD ISLAND CHEMISTRY 621A 1

FOREWORD

ForewordThe pan-Canadian Common Framework of Science Learning OutcomesK to 12, released in October 1997, will assist in standardizing scienceeducation across the country. New science curriculum for the AtlanticProvinces is described in Foundation for the Atlantic Canada ScienceCurriculum (1998).

Chemistry 521A includes the following topics: stoichiometry, fromstructures to properties, and organic chemistry.

Chemistry 621A includes the following topics: thermochemistry,from solutions to kinetics to equilibrium, acids and bases, andelectrochemistry.

This guide is intended to provide teachers with the overview of theoutcomes framework for Chemistry 621A. It also includes somesuggestions to assist teachers in designing learning experiences andassessment tasks.

3

INTRODUCTION

ATLANTIC CANADA SCIENCE CURRICULUM: PRINCE EDWARD ISLAND CHEMISTRY 621A

Introduction

Background

Aim

The curriculum described in Foundation for the Atlantic Canada ScienceCurriculum and in Chemistry 621A was planned and developedcollaboratively by regional committees. The process for developing thecommon science curriculum for Atlantic Canada involved regionalconsultation with the stakeholders in the education system in eachAtlantic province. The Atlantic Canada science curriculum is consistentwith the science framework described in the pan-Canadian CommonFramework of Science Learning Outcomes K to 12.

The aim of science education in the Atlantic provinces is to developscientific literacy.

Scientific literacy is an evolving combination of the science-relatedattitudes, skills, and knowledge students need to develop inquiry,problem-solving, and decision-making abilities; to become lifelonglearners; and to maintain a sense of wonder about the world aroundthem. To develop scientific literacy, students require diverse learningexperiences that provide opportunities to explore, analyse, evaluate,synthesize, appreciate, and understand the interrelationships amongscience, technology, society, and the environment.

5

PROGRAM DESIGN AND COMPONENTS


Program Design and Components

Learning andTeaching Science

What students learn is fundamentally connected to how they learnit. The aim of scientific literacy for all has created a need for newforms of classroom organization, communication, and instructionalstrategies. The teacher is a facilitator of learning whose major tasksinclude

• creating a classroom environment to support the learning andteaching of science

• designing effective learning experiences that help students achievedesignated outcomes

• stimulating and managing classroom discourse in support of studentlearning

• learning about and then using students’ motivations, interests,abilities, and learning styles to improve learning and teaching

• assessing student learning, the scientific tasks and activities involved,and the learning environment to make ongoing instructionaldecisions

• selecting teaching strategies from a wide repertoire

Effective science learning and teaching take place in a variety ofsituations. Instructional settings and strategies should create anenvironment that reflects a constructive, active view of the learningprocess. Learning occurs through actively constructing one’s ownmeaning and assimilating new information to develop a newunderstanding.

The development of scientific literacy in students is a function of thekinds of tasks they engage in, the discourse in which they participate,and the settings in which these activities occur. Students’ dispositiontowards science is also shaped by these factors. Consequently, the aim ofdeveloping scientific literacy requires careful attention to all of thesefacets of curriculum.

Learning experiences in science education should vary and shouldinclude opportunities for group and individual work, discussion amongstudents as well as between teacher and students, and hands-on/minds-on activities that allow students to construct and evaluate explanationsfor the phenomena under investigation. Such investigations and theevaluation of the evidence accumulated provide opportunities forstudents to develop their understanding of the nature of science and thenature and status of scientific knowledge.

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Communicating inScience

Learning experiences should provide opportunities for students touse writing and other forms of representation as ways to learning.Students, at all grade levels, should be encouraged to use writing tospeculate, theorize, summarize, discover connections, describeprocesses, express understandings, raise questions, and make sense ofnew information using their own language as a step to the languageof science. Science logs are useful for such expressive and reflectivewriting. Purposeful note making is an intrinsic part of learning inscience, helping students better record, organize, and understandinformation from a variety of sources. The process of creating webs,maps, charts, tables, graphs, drawing, and diagrams to represent dataand results helps students learn and also provides them with usefulstudy tools.

Learning experiences in science should also provide abundantopportunities for students to communicate their findings andunderstandings to others, both formally and informally, using a varietyof forms for a range of purposes and audiences. Such experiences shouldencourage students to use effective ways of recording and conveyinginformation and ideas and to use the vocabulary of science in expressingtheir understandings. It is through opportunities to talk and write aboutthe concepts they need to learn that students come to better understandboth the concepts and related vocabulary.

Learners will need explicit instruction in, and demonstration of, thestrategies they need to develop and apply in reading, viewing,interpreting, and using a range of science texts for various purposes. Itwill be equally important for students to have demonstrations of thestrategies they need to develop and apply in selecting, constructing, andusing various forms for communicating in science.

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An individual can be considered scientifically literate when he/she isfamiliar with, and able to engage in, three processes: inquiry,problem solving, and decision making.

The ThreeProcesses ofScientific Literacy

Inquiry

Problem Solving

Decision Making

Scientific inquiry involves posing questions and developingexplanations for phenomena. While there is general agreement thatthere is no such thing as the scientific method, students require certainskills to participate in the activities of science. Skills such as questioning,observing, inferring, predicting, measuring, hypothesizing, classifying,designing experiments, collecting data, analysing data, and interpretingdata are fundamental to engaging in science. These activities providestudents with opportunities to understand and practise the process oftheory development in science and the nature of science.

The process of problem solving involves seeking solutions to humanproblems. It consists of proposing, creating, and testing prototypes,products, and techniques to determine the best solution to a givenproblem.

The process of decision making involves determining what we, ascitizens, should do in a particular context or in response to a givensituation. Decision-making situations are important in their own right,and they also provide a relevant context for engaging in scientificinquiry and/or problem solving.

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Meeting the Needsof All Learners

Foundation for the Atlantic Canada Science Curriculum stresses theneed to design and implement a science curriculum that providesequitable opportunities for all students according to their abilities,needs, and interests. Teachers must be aware of, and makeadaptations to accommodate, the diverse range of learners in theirclass. To adapt instructional strategies, assessment practices, andlearning resources to the needs of all learners, teachers must createopportunities that will permit them to address their various learningstyles.

As well, teachers must not only remain aware of and avoid genderand cultural biases in their teaching; they must also actively addresscultural and gender stereotyping (e.g., about who is interested inand who can succeed in science and mathematics). Research supportsthe position that when science curriculum is made personallymeaningful and socially and culturally relevant, it is more engagingfor groups traditionally under-represented in science, and indeed, forall students.

While this curriculum guide presents specific outcomes for eachunit, it must be acknowledged that students will progress at differentrates.

Teachers should provide materials and strategies that accommodatestudent diversity, and should validate students when they achieve theoutcomes to the best of their abilities.

It is important that teachers articulate high expectations for all studentsand ensure that all students have equitable opportunities to experiencesuccess as they work toward achieving designated outcomes. Teachersshould adapt classroom organization, teaching strategies, assessmentpractices, time, and learning resources to address students’ needs andbuild on their strengths. The variety of learning experiences described inthis guide provide access for a wide range of learners. Similarly, thesuggestions for a variety of assessment practices provide multipleways for learners to demonstrate their achievements.

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The terms assessment and evaluation are often used interchangeably,but they refer to quite different processes. Science curriculumdocuments developed in the Atlantic region use these terms for theprocesses described below.

Assessment is the systematic process of gathering information onstudent learning.

Evaluation is the process of analysing, reflecting upon, andsummarizing assessment information, and making judgments ordecisions based upon the information gathered.

The assessment process provides the data, and the evaluation processbrings meaning to the data. Together, these processes improve teachingand learning. If we are to encourage enjoyment in learning for studentsnow and throughout their lives, we must develop strategies to involvestudents in assessment and evaluation at all levels. When students areaware of the outcomes for which they are responsible and of the criteriaby which their work will be assessed or evaluated, they can makeinformed decisions about the most effective ways to demonstrate theirlearning.

The Atlantic Canada science curriculum reflects the three majorprocesses of science learning: inquiry, problem solving, and decisionmaking. When assessing student progress, it is helpful to know someactivities/skills/actions that are associated with each process of sciencelearning. Student learning may be described in terms of ability toperform these tasks.

Assessmentand Evaluation

AssessmentTechniques

Assessment techniques should match the style of learning andinstruction employed. Several options are suggested in thiscurriculum guide from which teachers may choose, depending onthe curriculum outcomes, the class, and school/district policies. It isimportant that students know the purpose of an assessment, themethod used, and the marking scheme being used. In order thatformative assessment support learning, the results, when reported to

students, should indicate the improvements expected.

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Observation (formalor informal)

This technique provides a way of gathering information fairlyquickly while a lesson is in progress. When used formally, thestudent(s) would be made aware of the observation and the criteriabeing assessed. Informally, it could be a frequent, but brief, checkon a given criterion. Observation may offer information about theparticipation level of a student for a given task, use of a piece ofequipment or application of a given process. The results may berecorded in the form of checklists, rating scales or brief writtennotes. It is important to plan in order that specific criteria areidentified, suitable recording forms are ready, and that all students

are observed in a reasonable period time.

Performance This curriculum encourages learning through active participation.Many of the curriculum outcomes found in the guide promote skillsand their application. There is a balance between scientific processesand content. In order that students appreciate the importance ofskill development, it is important that assessment provide feedbackon the various skills. These may be the correct manner in which touse a piece of equipment, an experimental technique, the ability tointerpret and follow instructions, or to research, organize and presentinformation. Assessing performance is most often achieved through

observing the process.

Journal Although not assessed in a formal manner, journals provideopportunity for students to express thoughts and ideas in a reflectiveway. By recording feelings, perceptions of success, and responses tonew concepts, a student may be helped to identify his or her mosteffective learning style.Knowing how to learn in an effective way is powerful information.Journal entries also give indicators of developing attitudes to scienceconcepts, processes, and skills, and how these may be applied in thecontext of society. Self-assessment, through a journal, permits astudent to consider strengths and weaknesses, attitudes, interests,and new ideas. Developing patterns may help in career decisions

and choices of further study.

Interview This curriculum promotes understanding and applying scientificconcepts. Interviewing a student allows the teacher to confirm thatlearning has taken place beyond simply factual recall. Discussionallows a student to display an ability to use information and clarifyunderstanding. Interviews may be brief discussions between teacherand student or they may be more extensive and include student,parent, and teacher. Such conferences allow a student to be pro-active in displaying understanding. It is helpful for students to knowwhich criteria will be used to assess formal interviews. This assess-ment technique provides an opportunity to students whose verbal

presentation skills are stronger than their written.

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Paper and Pencil(assignment or test)

These techniques can be formative or summative. Several curriculumoutcomes call for displaying ideas, data, conclusions, and the resultsof practical or literature research. These can be in written form fordisplay or direct teacher assessment. Whether as part of learning, ora final statement, students should know the expectations for theexercise and the rubric by which it will be assessed. Writtenassignments and tests can be used to assess knowledge,understanding, and application concepts. They are less successfulassessing skills, processes, and attitudes. The purpose of theassessment should determine what form of pencil and paper exercise

is used.

Presentation The curriculum includes outcomes that require students to analyzeand interpret information, to identify relationships between science,technology, society, and environment, to be able to work in teams,and to communicate information. Although it can be timeconsuming, these activities are best displayed and assessed throughpresentations. These can be given orally, in written/pictorial form, byproject summary (science fair), or by using electronic systems such asvideo or computer software. Whatever the level of complexity orformat used, it is important to consider the curriculum outcomes as aguide to assessing the presentation. The outcomes indicate theprocess, concepts, and context for which and about which a

presentation is made.

Portfolio Portfolios offer another option for assessing student progress inmeeting curriculum outcomes over a more extended period of time.This form of assessment allows the student to be central in theprocess. There are decisions about the portfolio and its contentswhich can be made by the student. What is placed in the portfolio,the criteria for selection, how the portfolio is used, how and where itis stored, how it is evaluated, are some of the questions to considerwhen planning to collect and display student work in this way. Theportfolio should provide a long-term record of growth in learningand skills. This record of growth is important for individualreflection and self-assessment, but it is also important to share withothers. For many students, it is exciting to review a portfolio and see

the record of development over time.

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CURRICULUM OUTCOMES FRAMEWORK


Curriculum Outcomes Framework

Overview

Outcomes Framework

The science curriculum is based on an outcomes framework thatincludes statements of essential graduation learnings, general curriculumoutcomes, key-stage curriculum outcomes, and specific curriculumoutcomes. The general, key-stage, and specific curriculum outcomesreflect the pan-Canadian Common Framework of Science LearningOutcomes K to 12. The diagram below provides the blueprint of theoutcomes framework.

Essential GraduationLearnings

A Vision for ScientificLiteracy

in Atlantic Canada

Four General CurriculumOucomes:

Key-stage Curriculum Outcomes

Specific Curriculum Outcomes

SKILLSInitiating and planning

Performing and recordingAnalysing and interpreting

Communication and teamwork

KNOWLEDGELife science

Physical scienceEarth and space science

ATTITUDESAppreciation of science

Interest in scienceScience inquiry

Collaboration

Stewardship

Safety

FIGURE 1

STSENature of science and technology

Relationship betweenscience and technology

Social and environmental contextsof science and technology

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EssentialGraduation Learnings

Aesthetic Expression

Citizenship

Communication

Personal Development

Problem Solving

Technological Competence

Essential graduation learnings are statements describing theknowledge, skills, and attitudes expected of all students whograduate from high school. Achievement of the essential graduationlearnings will prepare students to continue to learn throughout theirlives. These learnings describe expectations not in terms of individualschool subjects but in terms of knowledge, skills, and attitudesdeveloped throughout the curriculum. They confirm that studentsneed to make connections and develop abilities across subjectboundaries and to be ready to meet the shifting and ongoingopportunities, responsibilities, and demands of life after graduation.The essential graduation learnings are:

Graduates will be able to respond with critical awareness to variousforms of the arts and be able to express themselves through the arts.

Graduates will be able to assess social, cultural, economic, andenvironmental interdependence in a local and global context.

Graduates will be able to use the listening, viewing, speaking,reading, and writing modes of language(s) as well as mathematicaland scientific concepts and symbols to think, learn, andcommunicate effectively.

Graduates will be able to continue to learn and to pursue an active,healthy lifestyle.

Graduates will be able to use the strategies and processes needed tosolve a wide variety of problems, including those requiring language,mathematical, and scientific concepts.

Graduates will be able to use a variety of technologies, demonstratean understanding of technological applications, and applyappropriate technologies for solving problems.

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Students will be encouraged to develop attitudes that support theresponsible acquisition and application of scientific and technologicalknowledge to the mutual benefit of self, society, and theenvironment.

GeneralCurriculumOutcomes

Science, Technology,Society, and theEnvironment

Skills

Knowledge

Attitudes

Key-StageCurriculumOutcomes

SpecificCurriculumOutcomes

The general curriculum outcomes form the basis of the outcomesframework. They also identify the key components of scientific literacy.Four general curriculum outcomes have been identified to delineate thefour critical aspects of students’ scientific literacy. They reflect thewholeness and interconnectedness of learning and should be consideredinterrelated and mutually supportive.

Students will develop an understanding of the nature of science andtechnology, of the relationships between science and technology, and ofthe social and environmental contexts of science and technology.

Students will develop the skills required for scientific andtechnological inquiry, for solving problems, for communicatingscientific ideas and results, for working collaboratively, and formaking informed decisions.

Students will construct knowledge and understandings of conceptsin life science, physical science, and Earth and space science, andapply these understandings to interpret, integrate, and extend theirknowledge.

Key-stage curriculum outcomes are statements that identify whatstudents are expected to know, be able to do, and value by the end ofgrades 3, 6, 9, and 12 as a result of their cumulative learning experiencesin science. The key-stage curriculum outcomes are from the CommonFramework for Science Learning Outcomes K to 12.

Specific curriculum outcome statements describe what students areexpected to know and be able to do at each grade level. They areintended to help teachers design learning experiences and assessmenttasks. Specific curriculum outcomes represent a framework for assistingstudents to achieve the key-stage curriculum outcomes, the generalcurriculum outcomes, and ultimately, the essential graduation learnings.

Specific curriculum outcomes are organized in units for each gradelevel.

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Attitude Outcomes It is expected that the Atlantic Canada science program will fostercertain attitudes in students throughout their school years. The STSE,skills, and knowledge outcomes contribute to the development ofattitudes, and opportunities for fostering these attitudes are highlightedin the Elaborations—Strategies for Learning and Teaching sections ofeach unit.

Attitudes refer to generalized aspects of behaviour that teachersmodel for students by example and by selective approval. Attitudesare not acquired in the same way as skills and knowledge. Thedevelopment of positive attitudes plays an important role in students’growth by interacting with their intellectual development and bycreating a readiness for responsible application of what studentslearn.

Since attitudes are not acquired in the same way as skills andknowledge, outcomes statements for attitudes are written as key-stagecurriculum outcomes for the end of grades 3, 6, 9, and 12. Theseoutcome statements are meant to guide teachers in creating alearning environment that fosters positive attitudes.

The following pages present the attitude outcomes from the pan-Canadian Common Framework of Science Learning Outcomes K to 12 forthe end of grade 12.

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Appreciation of Science

Common Framework of Science Learning Outcomes K to 12Attitude Outcome StatementsBy the end of grade 12, it is expected that students will be encouraged to

436 value the role and contributionof science and technology in ourunderstanding of phenomena that aredirectly observable and those that arenot

437 appreciate that the applicationsof science and technology can raiseethical dilemmas

438 value the contributions toscientific and technologicaldevelopment made by women andmen from many societies andcultural backgrounds

Evident when students, for example,

• consider the social and culturalcontexts in which a theorydeveloped

• use a multi-perspective approach,considering scientific,technological, economic,cultural, political, andenvironmental factors whenformulating conclusions, solvingproblems, or making decisionson STSE issues

• recognize the usefulness of beingskilled in mathematics andproblem solving

• recognize how scientific problemsolving and the development ofnew technologies are related

• recognize the contribution ofscience and technology to theprogress of civilizations

• carefully research and openlydiscuss ethical dilemmasassociated with the applicationsof science and technology

• show support for thedevelopment of informationtechnologies and science as theyrelate to human needs

• recognize that westernapproaches to science are not theonly ways of viewing the universe

• consider the research of bothmen and women

439 show a continuing and moreinformed curiosity and interest inscience and science-related issues

440 acquire, with interest andconfidence, additional scienceknowledge and skills using a variety ofresources and methods, includingformal research

441 consider further studies andcareers in science- and explore wherefurther science- and technology-related fields


• conduct research to answer theirown questions

• recognize that part-time jobsrequire science- and technology-related knowledge and skills

• maintain interest in or pursuefurther studies in science

• recognize the importance ofmaking connections betweenvarious science disciplines

• explore and use a variety ofmethods and resources to increasetheir own knowledge and skills

• are interested in science andtechnology topics not directlyrelated to their formal studies

• explore where further science- andtechnology-related studies can bepursued

• are critical and constructive whenconsidering new theories

• and techniques use scientificvocabulary and principles ineveryday discussions

• readily investigate STSE issues

442 confidently evaluate evidenceand consider alternative perspectives,ideas, and explanations

443 use factual information andrational explanations when analysingand evaluating

444 value the processes for drawingconclusions


• insist on evidence beforeaccepting a new idea orexplanation ask questions andconduct research to confirm andextend their understanding

• criticize arguments based on thefaulty, incomplete, or misleadinguse of numbers

• recognize the importance ofreviewing the basic assumptionsfrom which a line of inquiry hasarisen

• expend the effort and time neededto make valid inferences

• critically evaluate inferences andconclusions, cognizant of themany variables involved inexperimentation

• critically assess their opinion ofthe value of science and itsapplications

• criticize arguments in whichevidence, explanations, orpositions do not reflect thediversity of perspectives that exist

• insist that the critical assumptionsbehind any line of reasoning bemade explicit so that the validityof the position taken can bejudged

• seek new models, explanations,and theories when confrontedwith discrepant events or evidence

Scientific InquiryInterest in Science

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445 work collaboratively in planningand carrying out investigations, as wellas in generating and evaluating ideas


• willingly work with any classmateor group of individuals regardlessof their age, gender, or physicaland cultural characteristics

• assume a variety of roles within agroup, as required

• accept responsibility for any taskthat helps the group complete anactivity

• give the same attention andenergy to the group’s product asthey would to a personalassignment

• are attentive when others speak• are capable of suspending

personal views when evaluatingsuggestions made by a group

• seek the points of view of othersand consider diverse perspectivesaccept constructive criticismwhen sharing their ideas orpoints of view

• criticize the ideas of their peerswithout criticizing the personsevaluate the ideas of othersobjectively

• encourage the use of proceduresthat enable everyone, regardlessof gender or cultural background,to participate in decision making

• contribute to peaceful conflictresolution encourage the use of avariety of communicationstrategies during group work

• share the responsibility for errorsmade or difficulties encounteredby the group

Common Framework of Science Learning Outcomes K to 12

Attitude Outcome Statements (continued)

By the end of grade 12, it is expected that students will be encouraged toCollaboration

446 have a sense of personal andshared responsibility for maintaining asustainable environment

447 project the personal, social, andenvironmental consequences ofproposed action

448 want to take action formaintaining a sustainableenvironment


• willingly evaluate the impact oftheir own choices or the choicesscientists make when they carryout an investigation

• assume part of the collectiveresponsibility for the impact ofhumans on the environment

• participate in civic activitiesrelated to the preservation andjudicious use of the environmentand its resources

• encourage their peers or membersof their community to participatein a project related tosustainability

• consider all perspectives whenaddressing issues, weighingscientific, technological, andecological factors

• participate in social and politicalsystems that influenceenvironmental policy in theircommunity examine/recognizeboth the positive and negativeeffects on human beings andsociety of environmental changescaused by nature and by humans

• willingly promote actions that arenot injurious to the environment

• make personal decisions based ona feeling of responsibility towardless privileged parts of the globalcommunity and toward futuregenerations

• are critical-minded regarding theshort- and long-termconsequences of sustainability

449 show concern for safety andaccept the need for rules andregulations

450 be aware of the direct and indirectconsequences of their actions


• read the label on materials beforeusing them, interpret the WHMISsymbols, and consult a referencedocument if safety symbols are notunderstood

• criticize a procedure, a design, ormaterials that are not safe or thatcould have a negative impact onthe environment

• consider safety a positive limitingfactor in scientific andtechnological endeavours

• carefully manipulate materials,cognizant of the risks andpotential consequences of theiractions

• write into a laboratory proceduresafety and waste-disposal concerns

• evaluate the long-term impact ofsafety and waste disposal on theenvironment and the quality of lifeof living organisms

• use safety and waste disposal ascriteria for evaluating anexperiment

• assume responsibility for the safetyof all those who share a commonworking environment by cleaningup after an activity and disposingof materials in a safe place

• seek assistance immediately forany first aid concerns like cuts,burns, or unusual reactions

• keep the work station uncluttered,with only appropriate labmaterials present

Stewardship Safety in Science

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Curriculum GuideOrganization

Unit Organization

Specific curriculum outcomes are organized in units for each gradelevel. Each unit is organized by topic. Suggestions for learning,teaching, assessment, and resources are provided to support studentachievement of the outcomes. Suggested times for each topic are alsoprovided. Although Chemistry 621A is 110 hours in duration, thecummulative topic times allocated is 92 hours, or 46 hours per term.The remaining 9 hours each term allows for summative assessmentconsiderations.

The order in which the units of a grade appear in the guide is meantto suggest a sequence. In some cases, the rationale for therecommended sequence is related to the conceptual flow across theyear. That is, one unit may introduce a concept that is then extendedin a subsequent unit. Likewise, one unit may focus on a skill orcontext that will be built upon later in the year.

Some units or certain aspects of units may also be combined orintegrated. This is one way of assisting students as they attempt to makeconnections across topics in science or between science and the realworld. For example, solutions can be created during the FromSolutions To Kinetics To Equilibrium unit that can be later used inthe Acids and Bases or Electrochemistry units. In all cases, theintent is to provide opportunities for students to deal with scienceconcepts and scientific issues in personally meaningful and sociallyand culturally relevant contexts.

Each unit begins with a two-page synopsis. On the first page,introductory paragraphs provide a unit overview. These are followedby a section that specifies the focus (inquiry, problem solving, and/ordecision making) and possible contexts for the unit. Finally, acurriculum links paragraph specifies how this unit relates to scienceconcepts and skills addressed in other grades so teachers willunderstand how the unit fits with the students’ progress through thecomplete science program.

The second page of the two-page overview provides a table of theoutcomes from the Common Framework of Science Learning OutcomesK to 12 that the unit will address. The numbering system used is the onein the pan-Canadian document as follows:

• 100s—Science-Technology-Society-Environment (STSE) outcomes• 200s—Skills outcomes• 300s—Knowledge outcomes• 400s—Attitude outcomes (see pages 14–16)• ACCs—Atlantic Canada Chemistry outcomes

These code numbers appear in brackets after each specific curriculumoutcome (SCO).

Within each unit, the pan-Canadian outcomes are written in thecontext of Prince Edward Island’s Chemistry 621A curriculum.

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The Four-ColumnSpread

All units have a two-page layout of four columns as illustrated below.In some cases, the four-column spread continues to the nexttwo-page layout. Outcomes are grouped by a topic indicated at thetop of the left page.

Two-Page, Four-Column Spread

Topic

OutcomesElaborations—Strategies forLearning and Teaching

Tasks for Instruction and/orAssessment Resources/Notes

Students will beexpected to

• Specificcurriculumoutcome basedon the pan-Canadianoutcomes(outcomenumber)

• Specificcurriculumoutcome basedon the pan-Canadianoutcomes(outcomenumber)

elaboration of outcome andstrategies for learning andteaching

elaboration of outcome andstrategies for learning andteaching

Informal/Formal Observation

Performance

Journal

Interview

Paper and Pencil

Presentation

Portfolio

Provincialresponsibility

Page One Page Two

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Column One: Outcomes The first column provides the specific curriculum outcomes. Theseare based on the pan-Canadian Common Framework of ScienceLearning Outcomes K to 12. The statements involve the Science-Technology-Society-Environment (STSE), skills, and knowledgeoutcomes indicated by the outcome number(s) that appears inparenthesis after the outcome. Some STSE and skills outcomes havebeen written in a context that shows how these outcomes should beaddressed.

Specific curriculum outcomes have been grouped by topic. Othergroupings of outcomes are possible and in some cases may be necessaryto take advantage of local situations. The grouping of outcomesprovides a suggested teaching sequence. Teachers may prefer to plantheir own teaching sequence to meet the learning needs of theirstudents.

Column One and Column Two define what students are expected tolearn, and be able to do.

Column Two:

Elaborations—Strategiesfor Learning and Teaching

Column Three:Tasks for Instructionand/or Assessment

The third column provides suggestions for ways that students’achievement of the outcomes could be assessed. These suggestionsreflect a variety of assessment techniques and materials that include, butare not limited to, informal/formal observation, performance, journal,interview, paper and pencil, presentation, and portfolio. Someassessment tasks may be used to assess student learning in relation to asingle outcome, others to assess student learning in relation to severaloutcomes. The assessment item identifies the outcome(s) addressed bythe outcome number in brackets after the item.

The second column may include elaborations of outcomes listed incolumn one, and describes learning environments and experiencesthat will support students’ learning.

The strategies in this column are intended to provide a holisticapproach to instruction. In some cases, they address a single outcome;in other cases, they address a group of outcomes.

Column Four:Resources/Notes

This column provides an opportunity for teachers to make note ofuseful resources.

ATLANTIC CANADA SCIENCE CURRICULUM: PRINCE EDWARD ISLAND CHEMISTRY 621A22

THERMOCHEMISTRY

Thermochemistry (25 days, 30 hours)

Introduction Energy is the essence of our existence as individuals and as a society.An abundance of fossil fuels has led to a world appetite for energy.There are pros and cons to using fossil fuels. The relationshipbetween energy and chemistry needs to be explored to help us findalternative fuels. Thermochemistry includes energy changes thatoccur with physical and chemical processes. The study of energyproduction and the application of chemical change related topractical situations has helped society to progress.

Focus and Context Thermochemistry focuses on energy in various systems. Skillsinvolving planning, recording, analysing, and evaluating energychanges will be developed. Fuels for energy provide the context forstudent research and projects. These fuels could include energy forindustry, energy from foods, or any other relevant context. This unitwill help students to develop an interest in global energy issues andto appreciate the idea of possible solutions to a problem. Doing labwork and performing calculations allows students to discuss theirevidence and problem solving in order to consolidate theirunderstanding of energy change.

ScienceCurriculum Links

Science 7 outcomes included the explanation of temperature usingthe concept of kinetic energy and the particle model of matter. InScience 421A, students were introduced to balancing chemicalequations and the concepts of heat and temperature were developedin the context of weather topics. Chemistry 521A outcomes that areuseful for this unit include measuring/calculating amounts of moles,stoichiometry, and identifying fossil fuels.


THERMOCHEMISTRY

STSE Skills Knowledge

Students will be expected to Students will be expected to Students will be expected to

Curriculum Outcomes

Nature of Science and Technology

114-5 describe the importance ofpeer review in the development ofscientific knowledge

Relationships BetweenScience and Technology

116-4 analyse and describeexamples where technologies weredeveloped based on scientificunderstanding

Social andEnvironmental Contexts ofScience and Technology

117-6 analyse why scientific andtechnological activities take place ina variety of individual and groupsettings

117-9 analyse the knowledge andskills acquired in their study ofscience to identify areas of furtherstudy related to science andtechnology

118-2 analyse from a variety ofperspectives the risks and benefits tosociety and the environment ofapplying scientific knowledge orintroducing a particular technology

118-8 distinguish betweenquestions that can be answered byscience and those that cannot, andbetween problems that can besolved by technology and those thatcannot

118-10 propose courses of actionon social issues related to scienceand technology, taking into accountan array of perspectives, includingthat of sustainability

324-1 write and balance chemicalequations for combustion reactionsof alkanes

324-2 define endothermicreaction, exothermic reaction,specific heat, enthalpy, bondenergy, heat of reaction, and molarenthalpy

324-3 calculate and compare theenergy involved in changes of stateand that in chemical reactions

324-4 calculate the changes inenergy of various chemicalreactions using bond energy, heatsof formation and Hess’s law

324-5 illustrate changes in energyof various chemical reactions,using potential energy diagrams

324-6 determine experimentallythe changes in energy of variouschemical reactions

324-7 compare the molarenthalpies of several combustionreactions involving organiccompounds

Initiating and Planning

212-3 design an experimentidentifying and controlling majorvariables

212-8 evaluate and selectappropriate instruments forcollecting evidence and appropriateprocesses for problem solving,inquiring, and decision making

Performing and Recording

213-6 use library and electronicresearch tools to collect informationon a given topic

213-7 select and integrateinformation from various print andelectronic sources or from severalparts of the same source

Analysing and Interpreting

214-3 compile and display evidenceand information, by hand orcomputer, in a variety of formats,including diagrams, flow charts,tables, graphs, and scatter plots

214-6 apply and assess methods ofpredicting heats of reaction

214-15 propose alternative solutionsto a given practical problem, identifythe potential strengths andweaknesses of each, and select one asthe basis for a plan

Communication and Teamwork

215-4 identify multiple perspectivesthat influence a science-relateddecision or issue

215-6 work cooperatively with teammembers to develop and carry out aplan, and troubleshoot problems asthey arise

24 ATLANTIC CANADA SCIENCE CURRICULUM: PRINCE EDWARD ISLAND CHEMISTRY 621A

Outcomes

THERMOCHEMISTRY

Elaborations—Strategies for Learning and Teaching

Students will be expected to

• analyse why scientific andtechnological activities takeplace in a variety ofindividual and group settings(117-6)

The four outcomes listed here are discussed in terms of an STSEproject for students. References to the project occur throughout theunit. The section, “Science Decisions,” concludes the project or canbe used as a separate discussion. The outcomes are addressed as aSTSE question with connections from organic chemistry done inChemistry 11.

Assign a research project for this unit based on the question:Describe a scenario where a community and/or family has to select afuel and justify why it is best for a long-term plan. Students mightwork in groups for their research project. Reference to the researchproject can be made throughout the unit.

• analyse from a variety ofperspectives the risks andbenefits to society and theenvironment by applyingthermochemistry (118-2)

• distinguish between questionsthat can be answered usingthermochemistry and thosethat cannot, and betweenproblems that can be solvedby technology and those thatcannot (118-8)

• propose courses of action onsocial issues related to scienceand technology, taking intoaccount an array ofperspectives, including that ofsustainability (118-10)

Invite students to discuss and analyse the impact of fuel on scienceand technology. The risks and benefits of the fuels impact fromdifferent perspectives, such as health, economic, environmentalsafety, and chemical, could be analysed. A list could be made to helpstudents with their planning.

Students could describe the science and the technology that isneeded to commercially develop an energy source. An alternateperspective may be to identify an energy source and describe variousscience and technology considerations for its use.

Students should propose courses of action on questions which theyhave identified, and on answers which have supporting evidence. Asstudents look at their thermochemistry project proposal in terms ofscience, technology, society, and the environment, they should gainconfidence in their proposal and they will likely have moreunanswered questions.

Thermochemistry STSE3 days (3.5 hours)

25ATLANTIC CANADA SCIENCE CURRICULUM: PRINCE EDWARD ISLAND CHEMISTRY 621A

Tasks for Instruction and/or Assessment Resources/Notes

THERMOCHEMISTRY

Thermochemistry STSE3 days (3.5 hours)

Presentation

• Present your project using multimedia, audiovisual, or othersuitable format. Present your scenario to the class. The followingquestions might be helpful with your thinking:– What are the characteristics of a good chemical fuel?– What makes your fuel a good choice?– What is the most common method of producing your fuel?– What are some advantages of your fuel? Some disadvantages?– Outline the process of your fuel’s development.– What energy efficiency does your fuel have according to industry?– What impact will the fuel have on the local environment?(117-6, 118-2, 118-8, 118-10)

Journal

• Describe the magnitude of energy involved from physical,chemical, and nuclear processes. Provide an example of each typeof energy source (equation and energy value) and identify in whatcontext that the energy source could be used. (117-6, 118-2,118-8, 118-10)

MHR Chemistry, pp. 692-702

ThoughtLab “Comparing Energy Sources”

MHR Teacher’s Resource CD:

Additional Practice Problems, Chapter 17“Measuring and Using Energy Changes”

Performance Checklist:

# 3 - Performance Task Self Assessment

# 4 - Performance Task Group Assessment

MHR Website

P.E.I. Dept. of Education Website:

http://www.gov.pe.ca/go/science


Outcomes

THERMOCHEMISTRY



Science Decisions Involving Thermochemistry3 days (3.5 hours)

• describe the importance ofpeer review in thedevelopment of yourknowledge aboutthermochemistry (114-5)

• use library and electronicresearch tools to collectinformation on a given topic(213-6)

• select and integrateinformation from variousprint and electronic sources orfrom several parts of the samesource (213-7)

• identify multiple perspectivesthat influence a science-related decision or issueinvolving thermochemistry(215-4)

Teachers could address the following four outcomes as a part of theirstudents’ thermochemistry research projects as identified in the STSEsection, or as a separate discussion.

Students, in groups, should identify and describe sources of energyincluding present sources and possible new ones. Examples might benuclear, hydrogen, biomass, garbage, coal, peat, hydro, petroleum,natural gas, wind, and solar. Groups of two to four students couldidentify the influence science has on the development of the energysource by collecting information and presenting it to their peers.Other groups could question the development and the plans for theenergy.

Students should collect information through a library using booksand electronic research tools, for their STSE research project or for aparticular question the class wishes to discuss.

Students should cite the evidence in their research to support theirpositions. These sources need to be addressed as to their credibility,reliability, and specificity. For example, is a government source moreor less believable than a consumer source? Suggested perspectivesmight be governments, industry, industrial labour force, andconsumers.

Students might present their findings not as a written paper but as aspeech, brochure, short story, cartoon, or whatever form they choose.Their presentations should give the class an overview of possibilitieswhen deciding issues based on science.



THERMOCHEMISTRY

Science Decisions Involving Thermochemistry3 days (3.5 hours)

Paper and Pencil

• Select one of the following and research and organize informationabout it. Describe the science needed to commercially develop theenergy source. Possible topics: coal, petroleum, natural gas, sunbiomass, synthetic fuels, nuclear hydrogen, seed oil, methanol,geothermal (heat pumps), oil shale. (213-6, 213-7, 118-8)

• Prepare a newspaper article about your energy source and itspotential for energy production. Include information in your articleabout your energy source, such as its useable lifetime as a commercialsource, impact on the environment, appeal to an individualconsumer, and/or appeal to a community of consumers.(114-5, 213-6, 213-7, 215-4)

• Consider climatic, economic, and supply factors in your search foran energy source for the future. Include these in the research projectthat you began at the beginning of this unit.(114-5, 213-6, 213-7, 215-4)


ThoughtLab “Comparing Energy Sources”






MHR Website




Outcomes

THERMOCHEMISTRY



Enthalpy Changes10 days (12 hours)

• define endothermic reaction,exothermic reaction, specificheat, enthalpy, bond energy,heat of reaction, and molarenthalpy (324-2)– define thermochemistry and

thermodynamics– differentiate between

endothermic and exothermicchanges

– calculate specific heat capacity– use specific heat capacity in

calculations

Students should define thermodynamics and thermochemistry.Students should differentiate between endothermic and exothermicchanges. Bond energy, enthalpy, molar enthalpy, and heat of reactionshould be discussed; however, these will be referred to again later inthis unit.

Ask students for everyday examples involving endothermic andexothermic changes. Example might include heating and freezing ofice, hot and cold packs, evaporation and condensation of water, andproduction and decomposition of ammonia.

Students could be introduced to a discussion of the Law ofConservation of Energy and the 1st Law of Thermodynamics. Havestudents pose questions about types of systems and the energychanges that occur within them.

Students should investigate heating and cooling and phase changesin terms of forces between particles, particle movement, heat contentand changes in potential energy. Changes to particle movement insystems in terms of change in temperature could be introduced.Changes in potential energy in matter should be discussed; however,these will be referred to again later in this unit when calculatingenergy involved in changes in state.

Students should calculate specific heat capacity and performcalculations involving specific heat capacity. Students shouldqualitatively and quantitatively describe the resulting temperaturewhen two substances are mixed together. The relatively high specificheat capacity of water should be investigated. Invite students torelate the importance of this quantity to issues such as climatecontrol, heat delivery in homes, and coolant in vehicles and homes.



THERMOCHEMISTRY


Paper and Pencil

• Distinguish between temperature and heat by relating these tothe energy of the atoms and molecules. (324-2)

• Which has more heat: water in a 250 mL cup at 40°C or water ina 200 mL flask at 40°C? Qualitatively and quantitatively explainyour result. (324-2)

• Which would cause a more severe burn: 100 g of water at 100°Cor 100 g of steam at 100°C? Give reasons to support yourdecision. (324-2)

• Calculate the heat gained or lost from the following system:– A cold piece of metal having a mass of 100 g, originally at –30°C,

was dropped in 300 g of warm water at 35°C. The temperature ofthe water went down to 32°C. Calculate the specific heat of thatmetal. (324-2)

• Heat lost equals heat gained. Explain this assumption. (324-2)• Liquid water turns to ice. Is this endothermic or exothermic?

Explain. (324-2)• Explain what is meant by the following terms: specific heat, heat of

reaction, and molar enthalpy. (324-2)• Explain why a watch glass containing ammonium nitrate feels

cold when water is added. (324-2)

Journal

• A Scottish chemist, Joseph Black (1728–1799), differentiatedbetween temperature and thermal energy. Discuss how these aredifferent. Give an example of an experiment to show that twoobjects at the same temperature do not necessarily have the samethermal energy. (324-2, 212-3)

• In your journal, respond to the following questions:– Explain why, on a hot summer day at the beach, the sand can

be unbearably hot on bare feet yet the water is very cold.– What happens when direct sunlight is blocked by a cloud?

How does this affect the sand’s versus the water’s temperature?(324-2)

Presentation

• Fire in a fireplace is started by lighting crumpled paper under logswith a match. In groups, discuss the energy transfers using theterms potential energy, kinetic energy, kindling temperature,system, surroundings, endothermic, and exothermic. Presentyour finding to the class (324-2)

MHR Chemistry, pp. 624 - 637

ThoughtLab “Factors in Heat Transfer”

Appendix E “Table E10: Specific HeatCapacities of Various Substances” p. 847



MHR Website



Chem. Lab. “Heat Capacity of a Metal”

Formal Laboratory Report Format

Science Safety Manual


Outcomes

THERMOCHEMISTRY




• illustrate changes in energy ofvarious chemical reactions,using potential energydiagrams (324-5)– identify exothermic and

endothermic processes fromthe sign of HΔ , fromthermochemical equations, andfrom labelled enthalpy/potential energy diagrams

– label enthalpy diagrams giveneither the HΔ for a process ora thermochemical equation

Students should be able to identify exothermic and endothermicprocess from the sign of HΔ , from thermochemical equations, andfrom labelled enthalpy/potential energy diagrams. Connectionsshould be made between these three methods of illustratingthermochemical changes. Using an exothermic reaction as anexample, students could use the terms high and low to represent theenergy levels of the reactants and products, respectively. The studentwould then identify the enthalpy change for the exothermic reactionas being negative (ÄH

RXN = H

final (low) - H

initial (high) = negative).

The student should then recognize that energy was lost, or released,and as a result place the relative energy value on the product side ofthe thermochemical equation.

Students should be able to label enthalpy diagrams given either the

HΔ for a process or a thermochemical equation. Teachers mightshow examples that students are considering for their researchproject.

• compile and display evidenceand information on heats offormation in a variety offormats, including diagrams,flow charts, tables, and graphs(214-3)– write thermochemical equations

including the quantity of energyexchanged given either thevalue of HΔ or a labelledenthalpy diagram, and vice versa

Students should be able to write thermochemical equationsincluding the quantity of energy exchanged given either the value of

HΔ or a labelled enthalpy diagram, and vice versa.

All of these might be explored through written explanations with thediagrams and thermochemical equations. Sample tables and/orgraphs are useful visual tools that might help students to clarify theconcepts. Whether the diagrams are prepared by hand or computer,the presentation needs to focus on clarity, content, and readabilityfor others’ understanding.



THERMOCHEMISTRY


Journal

• What types of potential energy have I used during this day? Makea chart. (214-3)

• As a living person, my energy exchange position is exothermic.Reflect on this statement. (324-5, 214-3)

Paper and Pencil

• Draw and label a potential energy (enthalpy) diagram for each ofthe following:– exothermic– endothermic (324-5, 214-3)

• Given various potential energy diagrams, determine whether thereaction is exothermic or endothermic. Identify the reactants andproduct, and determine the amount of energy involved. Write averbal interpretation. (324-5, 214-3)

• Given a thermochemical equation, draw and label thecorresponding energy level diagram. Identify the reactants andproduct, and determine the amount of energy involved. Write averbal interpretation. (324-5, 214-3)

Presentation

• For a selected reaction, make the case that the Law ofConservation of Energy has been “upheld.” Use equations anddiagrams in your arguments. (324-5, 214-3)




MHR Website




Outcomes

THERMOCHEMISTRY




• calculate and compare theenergy involved in chemicalreactions (324-3a)– write thermochemical equations

to represent enthalpy notation,

combHΔ , fHΔ , ÄHvap

– calculate the heat gained or lostfrom a system using thethermochemical equation

Students should write thermochemical equations to represent

enthalpy notation, combHΔ and fHΔ . Students should define thestandard molar enthalpy of various chemical processes (combustion,formation, reaction). Students should calculate the heat gained orlost from a system using the thermochemical equation and thereactant data. In groups, one student could calculate the heatinvolved from a given mass and the other could recalculate the givenmass from the calculated heat term. Calculating the heat absorbed orreleased should be performed using the stoichiometry conceptslearned in 521A.

Students should define molar enthalpy of various physical processes(soln, vap, cond, melt, freez)

Students should calculate the total heat for a multi-step process suchas: How much heat is required to heat 50 g of ice at –20°C to steamat 120°C. Students could draw and label a heating/cooling curvewhich shows changes in kinetic versus potential energy. Studentscould explain in words, what is happening with the heat andinterpret, with words, various curves. Teachers might discuss withstudents the motion of particles as the substance has a temperatureor state change and relate each change to the kinetic theory of

matter. It is suggested that the student use the formulas q mc T= Δfor changes in kinetic energy (change in temperature), andq n H= Δ for changes in potential energy (changes in state).

• compare the molar enthalpiesof several combustionreactions involving organiccompounds (324-7)

Have students make a list of fossil fuels. Students could indicatewhere they see these fuels used, compare the molar enthalpy ofcombustion values and write combustion equations for the fuels.

Students should balance complete alkane combustion reactions usingup to ten carbon atoms. Equations, including molar enthalpies ofpossible combustion reactions, could be identified. As studentsbecome familiar with energy and thermochemistry throughout thisunit theycould add to their project information. The completecombustion of hydrocarbons produces carbon dioxide, CO

2, and

water, H2O. Showing students the molar enthalpies will help them

realize the importance of energy.

CH4(g) + 2O

2(g) → CO

2(g) + 2H

2O(g) + energy (heat)

CH4(g) + 2O

2(g) →CO

2(g) + 2H

2O(g) + 803kJ

2C3H

6(s) + 9O

2(g) → 6CO

2(g) + 6H

2O + 4119kJ

• calculate and compare theenergy involved in changes ofstate (324-3b)– calculate the heat gained or lost

from a system using the

formulas q mc T= Δ and

q n H= Δ

• write and balance chemicalequations for combustionreactions of alkanes, includingenergy amounts (324-1)



THERMOCHEMISTRY


Paper and Pencil

• Write a balanced chemical equation for the combustion reactionof each of these alkanes: methane, ethane, propane, butane, andoctane. (324-1)

• Look up the molar enthalpies of the combustion of butane andoctane. What do they have in common? (324-7)

• Calculate and compare the amount of heat released from thecomplete combustion of 1 kg of propane and 1 kg of butane.(324-1, 324-7, 324-3a)

• Calculate the amount of heat involved when 2.0 g of Calciumchloride dissolves. (324-3b)

• Calculate the amount of heat involved when 3.0 g of ice melts atits melting point. (324-3b)

• Linda wants to know how much heat energy is released when 25kg of steam at 100°C is cooled to 25 kg of ice at –15°C. Calculatethe total heat energy released. (324-3b)

• Describe the processes involved in heating a substance fromtemperatures below its freezing point to temperatures above itsboiling point. Indicate which of these processes involve change inpotential energy and which involve changes in kinetic energy.(324-3b)

Journal

• Given the molar enthalpy of combustion for propane, describewhat must be done prior to including the enthalpy term as aproduct in the thermochemical equation.




MHR Website





Outcomes

THERMOCHEMISTRY



Thermochemistry Experimentation4 days (5 hours)

• work cooperatively with teammembers to develop and carryout thermochemistryexperiments (215-6)

• evaluate and selectappropriate instruments forcollecting evidence andappropriate processes forproblem solving andinquiring (212-8)

• determine experimentally thechanges in energy of variouschemical reactions (324-6)

The following six outcomes are discussed in terms ofthermochemistry experimentation. Students should develop anunderstanding of calorimetry and identify the instruments involvedwith calorimetry. The Law of Conservation of Energy and the 1stlaw of Thermodynamics, discussed earlier, are put into practical use.Observing the quantity of energy involved in physical and chemicalprocesses will allow students to relate to the magnitude of energyinvolved in nuclear and biological processes. Students could performtheoretical calculations. For example, based on the energy valuesthey obtained from their experiments, they could determine thequantity of heat that would be involved if more reactant were used.

Having collected empirical data from various experiments, studentsshould explore practical situations involving heat and energy transfer,such as a fire in a fireplace, solar collectors, eating food to fuel yourbody, or photosynthesis. Students should compare physical,chemical, and nuclear changes in terms of the species and themagnitude of energy changes involved. This works well withestimation.

• analyse the knowledge andskills acquired in their studyof thermochemistry toidentify areas of further studyrelated to science andtechnology (117-9)– compare physical, chemical,

and nuclear changes in termsof the species and themagnitude of energy changesinvolved

• propose alternative solutionsto solving energy problemsand identify the potentialstrengths and weaknesses ofeach (214-15)– explain, in simple terms, the

energy changes of bondbreaking and bond formation

Students should explain, in simple terms, the energy changes ofbond breaking and bond formation. The formation of bonds and theenergy could be related to why some changes are exothermic whileothers are endothermic. Later in this unit, students will be able tocalculate the energy involved in a chemical reaction using bondenergies.

• design a thermochemistryexperiment identifying andcontrolling major variables(212-3)

As an introduction to calorimetry, students should perform a lab onheat of fusion of ice or wax. Having been introduced to calorimetryand calorimetry techniques, students could design an experiment todetermine the specific heat capacity of a metal or enthalpy ofsolution. With a partner, students should select appropriate labequipment, quantities of materials, and data in the experiments.

As an introduction to calorimetry involving chemical reaction, a heatof combustion experiment could be performed such that the systemand surrounding are easily identifiable. A heat of neutralizationexperiment or another experiment involving a chemical reactionoccurring in solution could be performed.



THERMOCHEMISTRY

Paper and Pencil

• As you plan one of your experiments for this unit, list the skillsand knowledge needed to perform the experiment properly.(117-9)

• HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)

When 50.0 mL of 1.00 mol/L HCl(aq) and 50.0 mL of 1.00mol/L NaOH(aq) are mixed in a Styrofoam cup calorimeter, thetemperature of the resulting solution increases from 21.0°C to27.5°C. Calculate the heat of this reaction measured in kilojoulesper mole of HCl(aq). (324-2, 324-3a, 324-3b, 324-6)

• Define a practical problem with an energy change. Propose asolution. (214-15)

Performance

• With a partner, design a lab to calculate the molar heat ofsolution of NH

4NO

3 and of CaCl

2. Include safety issues that

should be addressed. After your plan is approved, carry out yourprocedure and collect evidence (data) and report your findings.(212-3, 215-6, 212-8, 324-2, 324-3)

• Select and use appropriate equipment to make an inexpensivehand warmer. (Hint: Use these substances: powdered iron; H

2O;

NaCl; and vermiculite.) Design your experiment. Consider safetyprecautions. If approval is obtained, do this experiment. Havesomeone test your results. (212-3, 215-6, 212-8, 324-6)

Journal

• The calorimeter is the basic instrument for measuring heattransfer. Explain how it measures heat transfer, and how it works.(212-8)

• Write the thermochemical equation for each of the experimentsthat you performed during this unit. Compare the magnitude ofa nuclear change and the biological process of converting ATP toADP to the experimental values that you experienced.(117-9, 214-15)

Portfolio

• Include your laboratory report(s) in your Chemistry portfolio.(212-3, 324-6)

Thermochemistry Experimentation4 days (5 hours)

MHR Chemistry, pp. x-xiii, 660-672

Investigation 17-A “Determining theEnthalpy of a Neutralization reaction”

Investigation 17-B “The Enthalpy ofCombustion of a Candle”

ExpressLab “The Energy of Dissolving”

ExpressLab “Construct a Heating Curveand a Cooling Curve”




#1 - Designing an Experiment

# 2 - Laboratory Report



Unit 7

Additional Investigation A “CampStove Efficiency”

Additional Investigation B “The MolarHeat of Freezing of Paraffin Wax”

MHR Website



Chemistry Lab “Heat of Reaction”

Chemistry Lab “Heat Capacity of aCalorimeter”




Outcomes

THERMOCHEMISTRY



Bonding and Hess’s Law5 days (6 hours)

• calculate the changes inenergy of various chemicalreactions using bond energy,heats of formation, and Hess’sLaw (324-4)

• analyse and describe exampleswhere technologies weredeveloped based onunderstandingthermochemistry (116-4)

Students should demonstrate an understanding that there aredifferent ways of determining HΔ : Hess’s Law, average bond energy,enthalpy of formation, and use of calorimeters/experimentation.

Students should use the method of adding of chemical equations andcorresponding enthalpy changes to compute the enthalpy change ofthe overall process, which is Hess’s Law. Students might address thequestion, “Why is Hess’s Law useful?” Hess’s Law could determine

HΔ of a reaction that otherwise might be too difficult, expensive, ordangerous to perform.

Students should use bond energies to calculate the enthalpy changefor an overall process. Propanol could be used as an example.Calculate the total energy required to break the compound intoatoms. Students could calculate the overall energy change for thereaction, which is the enthalpy of combustion reaction for propanol.This might be a good application to be included in students’ongoing STSE research projects.

Students should be able to use a standard heat of formation table topredict enthalpy of reaction for a chemical change.

Students should conduct a Hess’s Law experiment. Before doingtheir experiment involving Hess’s Law, students should be aware ofthe instruments involved in their experiment. Students could explorenew instruments/technologies that would help them to do the labmore accurately and efficiently.

Students could select an experiment suggested in ThermochemistryExperimentation, such as the heat of neutralization, and comparethe experimentally determined lab value to the theoretical valueobtain from heat of formation data or bond energy data.

Students should analyse and describe examples where technologieswere developed. The use of “heat sinks”, which are usually metalobjects attached to components of electrical circuitry which absorband dissipate heat efficiently, is an example that could be analysedand described.

• apply one of the methods ofpredicting heats of reactionsto your experimentallydetermined lab values(214-6)– conduct a Hess’s Law

experiment– compare experimental results to

theoretical calculations fromheat of formation or bondenergy data



THERMOCHEMISTRY

Bonding and Hess’s Law5 days (6 hours)

Performance

• Perform an experiment involving Hess’s Law. (324-4, 214-6)Presentation

• Create an analogy to Hess’s law and present your analogy to theclass (324-4)

Journal

• Would you rather drink hot chocolate out of a cup made of glass,a ceramic mug, or a cup insulated with a styrofoam layer?Explain your reasoning. (116-4)

• You are told to use a balance to find the mass of your substancewhen it is at room temperature. Explain this statement. (116-4)

Paper and Pencil

• Calculate HΔ , using Hess’s Law for

4NH3(g) + 3O

2(g) → 2N

2(g) + 6H

2O(l)

given the following reactions and HΔ values:

– 2NH3(g) + 3N

2O(g) → 4N

2(g) + 3H

2O(l) ΔH = –1012kJ

– 2N2O(g) → 2N

2(g) + O

2(g) ΔH =–164kJ (324-4)

• From your knowledge of standard states and from an enthalpy offormation chart, list the standard enthalpy of formation of each ofthe following substances: (324-4)

a) Cl2(g) c) C

3H

6(g) e) H

2O(g)

b) H2O(l) d) Na(s) f ) P

4(g)

• Calculate HΔ for the following reaction:

2C3H

6(g) +9O

2(g) → 6CO

2(g) + 6H

2O(l) (324-4)

• Calculate the heat of formation, Δ fH , of NO2.

N2(g) + 2O

2(g) → 2NO

2(g) HΔ =+16.2kJ (324-4)

• Hydrazine, N2H

4(g), is used as a fuel in liquid-fuelled rockets. It can

react with O2(g) or N

2O

4(g) both producing N

2(g) and H

2O(g).

Write balanced chemical equations for the two reactions. Calculate

HΔ for each reaction, using information from an enthalpy table.Compare the values. Which is the more efficient rocket fuel?(324-4)

• Choose one of the experiments performed during this unit anduse enthalpy of formation values or bond energies to calculate atheoretical value of enthalpy of reaction. Compare the theoreticaland experimental value of enthalpy of reaction. (214-6)

Portfolio

• Include your laboratory report(s) in your chemistry portfolio.(213-3, 324-6)


Investigation 17-c “Hess’s Law and theEnthalpy of Combustion of Magnesium”

Appendix E “Table E.11 Average BondEnergies” p.847

Appendix E “Table E.13 Standard MolarEnthalpies of Formation” p.848







MHR Website



Chemistry Lab “Heat of Reaction for theCombustion of magnesium (Hess’s Law)”



ATLANTIC CANADA SCIENCE CURRICULUM: PRINCE EDWARD ISLAND CHEMISTRY 621A38

FROM SOLUTIONS TO KINETICS TO EQUILIBRIUM

Focus and Context


Investigation of change in the context of solutions helps students todevelop their understanding about mixtures, solutions, bonding, andstoichiometry. This investigation leads to factors which affect the ratesof chemical reactions, chemical equilibrium, and a quantitativetreatment of reaction systems. The balance of opposing reactions inchemical equilibrium systems has issues relating to commercial/industrial production.

Many factors affect the rate of chemical reactions. Understandingthat reactions can be described as dynamic equilibrium systems bycriteria, equations, calculations, concentrations, and experimentswithin the context of everyday phenomena is the focus of this uniton solutions and equilibrium. The context might be hemoglobin athigh altitudes, ammonia in the Haber process, CaCO

3 in caves, acids

corroding metals, sodium carbonate in the Solvay process, or anyother relevant context.

Problem-solving skills are used throughout this unit. Identifyingvariables and performing experiments to test equilibrium shifts andreaction rates are valuable to understanding this unit.

In Science 421A, students interpreted and balanced chemicalequations. Chemistry 521A introduced ions, ionic compounds,molecular structure, and solubility as well as measuring amounts inmoles. In Chemistry 621A, before expressing the concept ofequilibrium, the concentration of solutions should be addressed.

Introduction

From Solutions to Kinetics to Equilibrium(13 days , 16 hours)

39






114-2 explain the roles ofevidence, theories, and paradigmsin the development of scientificknowledge


116-2 analyse and describeexamples where scientificunderstanding was enhanced orrevised as a result of the inventionof a technology

116-4 analyse and describeexamples where technologies weredeveloped based on scientificunderstanding


117-7 identify and describescience- and technology-basedcareers related to the science theyare studying


212-9 develop appropriatesampling procedures


213-1 implement appropriatesampling procedures

213-5 compile and organizedata, using appropriate formatsand data treatments to facilitateinterpretation of data

321-3 identify and discuss theproperties and situations inwhich the rate of reaction is afactor

ACC-1 describe collision theoryand its connection to factorsinvolved in alerting reaction rates

ACC-2 describe a reactionmechanism and catalysts’s role in achemical reaction

323-3 define the concept ofequilibrium as it pertains tosolutions

323-5 explain how differentfactors affect solubility, using theconcept of equilibrium

323-6 determine the molarsolubility of a pure substance inwater

Curriculum Outcomes

40

Outcomes





Solution Concentration3 days (3.5hours)

• identify and describe science-and technology-based careersrelated to solutions andequilibrium (117-7)

Students should identify a career related to solutions andconcentration. A description of the career, the importance ofsolubility and concentration, and the technology involved could bepresented in creative formats. These career choices could look atpreventing lead poisoning by removing lead from paint, destroying afish shipment containing a higher than legal limit of mercury,mixing gasoline and oil for boat motors, identifying theconcentration of contaminants in drinking water, identifyingconcentration of various substances (iron, cholesterol, etc) in blood,or any other relevant context. A laboratory technologist, hospitaltechnologist, and a chemical engineer are examples.

• determine the molarsolubility of a pure substancein water (323-6)– calculate the concentration in

mol/L or molarity, M, ofsolutions based on mass and/ormoles of the solute (or soluteions) and volume of the solution

– know that [ ] always impliesconcentration in mol/L

– perform experiments involvingthe creation of stock solutionsand relevant calculations

– perform experiments involvingdilutions and relevant dilutioncalculations

Students should be able to calculate the molar concentration(molarity) in mol/L, or M, of solutions based on mass and/or molesof the solute and volume of the solution. Students should makestock solutions in the lab of a specified concentration and volume.The solution types and concentrations could be based on solutionsthat may be required in further experiments for qualitative analysis(precipitate experiments, electrochemical cells, etc). Solutionsshould contain appropriately labelled WHMIS labels.

Students could perform an experiment involving dilutions. Astandard curve could be constructed from dilutions of a stocksolution. The curve could be used to determine the concentration ofan unknown. Various methods could be employed to detect solutionconcentration such as specific gravity (specific gravity vs [ ]) andlight absorption (absorption vs [ ]). This is an ideal opportunity forstudents to use graphing technology such as the TI-83 graphingcalculator. Student could enter the data and have the calculator plotthe corresponding graph. Using the linear regression feature, a linearequation can be obtained and used to calculate the concentration of asolution given the measured value (specific gravity or absorbance).Alternatively, students could also use the trace feature on thecalculator to identify the concentration of the unknown.

41




Solution Concentration3 days (3.5hours)

Performance

• Prepare 1.0 L of a 0.50 M stock solution of NaOH. (323-6)• Perform an experiment involving dilutions of a stock solution.

(323-6)

• Perform an experiment to determine the approximate concentrationof a solution given only a sample of the solution and access to labequipment. Write a theory and procedure for the experiment. Ifthe procedure is approved by your teacher, perform theexperiment. (Assume the density of pure water is 1.00g/ml)

Journal

• What do you need to know in order to calculate the molarity of asolution? Explain. (323-6)

• Outline the steps required to prepare or dilute a solution to aspecific concentration. (323-6)

• When performing a dilution, describe why the moles of solute iscommon to the aliquot of concentrated solution obtained and thedilute solution. (323-6)

Paper and Pencil

• Which solution would contain the largest mass of solute? Thesolute is Na

2SO

4 and the solvent is H

2O. (323-6)

a) 0.12 M in 500 mL c) 0.67 M in 199 mLb) 0.23 M in 200 mL d) 0.080 M in 1000 mL

• Which solution would contain the largest mass of solute? The solventis H

2O. (323-6)

a) 0.13 M of Na2SO

4 in 100 mL c) 0.62 M of AlCl

3 in 500 mL

b) 0.42 M of NaCl in 100 mL d) 0.87 M of AlF3 in 1200 mL

• Calculate the molarity, M, of a sodium chloride solution that has avolume of 300.0 mL and contains 25.0 g of NaCl? (323-6)

Presentation

• With a partner, make a solution of CuSO4 • 5H

2O of a known

molarity. Pour various volumes of the blue liquid into 3 test tubes.Answer the following questions:– Which contains the most solute?– Which has the highest concentration?– How was this judgment made?– Do these solutions have the same or different number of ions per

unit volume?– Why are there varying depths of colour?Present your answers to the class (323-6)

• In a pictorial or photo-essay, demonstrate the use of solutions andprecipitates as related to a career of your choice. (117-7)

Portfolio

• Include your laboratory report(s) in your chemistry portfolio. (323-6)

MHR Chemistry, pp. x-xiii, 255-276,

299-308

Careers in Chemistry “ProductDevelopment Chemist”

Chemistry Bulletin “Water Quality”

Investigation 7-B “Determining theConcentration of a Solution”

Investigation 7-C “Estimating theConcentration of an Unknown Solution”


Additional Practice Problems, Chapter 7“Solutions and their Concentrations”

Unit 3 Additional Investigation-B“Determining Concentration bySpectrophotometric Measurements”

Unit 3 Additional Investigation-B“Determining Molar Concentration usingStoichiometry”





MHR Website



Chem. Lab “Colorimetry”

Chem. Lab “Preparing a Stock Solution/Performing Dilutions”

Chem. Lab “Preparation of a StandardSolution”



42

Outcomes





• identify and discuss theproperties and situations inwhich the rate of reaction is afactor (321-3)– identify the factors that affect

rate of reaction and how thesecan be controlled

– perform an experiment todetermine the factors that affectthe rate of a chemical reaction

Students should identify the factors that affect rate of reaction andthe ways these can be controlled (temperature, concentration, surfacearea, catalysts, and nature of the reactants). Students should applytheir knowledge to explain reactions in different situations.

Students could investigate the role of surface area, temperature,concentration, and catalyst by performing lab experiments such asyeast and sugar solution or antacid tablets and water. Discussion interms of reaction kinetics would be appropriate here.

In groups of four, students could identify common reactions whoserates can be controlled and the processes used to control them. Whenresults are presented to the class, additions or deletions could also berecorded.

Students could design and carry our experiments to collect data ofthe rate of a simple reaction. Interpreting their data might require agraph. Suggested reactions include a metal with an acid, baking sodawith vinegar, or antacid with water. Discussion about slow and fastchemical reactions might give information about why it is importantto control the rates of reactions. Students could explore relatedexamples such as rust prevention and an air bag reaction. Examplesof reactions from biochemistry might be an interesting extension.

Kinetics and Rate of Reaction1.5 days (2hours)

43




Kinetics and Rate of Reaction1.5 days (2hours)

Journal

• Why is it better to use a catalyst to speed up a reaction ratherthan increase the temperature? (321-3)

Paper and Pencil

• When is it desirable to speed up a chemical reaction? (321-3)• When is it desirable to slow down a chemical reaction? (321-3)• Why is it easier to light pieces of kindling wood for a fire rather

than a log? (321-3)

Paper and Pencil

• Perform an experiment that tests the factors that affect the rate ofa chemical reaction. (321-3)

Portfolio

• Include your laboratory report(s) in your chemistry portfolio.(323-1)


Investigation 12-A “Factors that Affect theRate of Reaction”

Tools and Techniques “Methods forMeasuring Reaction Rates”


Additional Practice Problems, Chapter 12“Rates of Chemical Reactions”

Unit 5 Additional Investigation-A “TheIodine Clock Reaction”

Unit 5 Additional Investigation-B “FactorsAffecting the Rate of Reaction”





MHR Website



Chem. Lab “The Clock Reaction”



44

Outcomes





Collision Theory, Reaction Mechanisms, and Catalysts1.5 days (2 hours)

• describe collision theory andits connection to factorsinvolved in altering reactionrates (ACC-1)– describe the role of the

following in reaction rate:nature of reactants, surfacearea, temperature, catalyst, andconcentration

– explain how various factors canaffect the rate of a reaction usingthe kinetic molecular theory andcollision theory

Students should describe the role of the following in reaction rate:nature of reactants, surface area, temperature, catalyst, andconcentration. Students should perform experiments and havediscussions to determine the factors that affect the rate of a chemicalreaction.

A classroom analogy could be performed where the studentsrepresent the reacting particles. The students should be asked todemonstrate an understanding of how the frequency of studentcollisions can be increased and how this concept can be related tocollision theory and altering reaction rates. Various classroomconditions can be altered such as the area in which the “studentparticles” can move (concentration), or the speed of “studentparticle” movement (temperature).

Students could perform lab experiments to predict which reactionthey think would be faster. Demonstrating the reactions betweenvarious solutions, students might discuss the role “the nature ofreactants” plays in the rates of reactions. Students should be able todemonstrate an understanding of the fundamentals of the kineticmolecular theory and collision theory using potential energydiagrams and energy considerations. Controlling reaction rates isimportant in many commercial and industrial processes. By applyingcollision theory to the rates of fast and slow reactions, studentsshould be asked for complete and detailed explanations using thecorrect terminology.

45




Performance

• Students could role play as moving molecules. An example couldbe students moving and colliding within an entire classroomversus using only half of this space (higher concentration)

(ACC-1)

Presentation

• Develop an analogy to describe why certain factors affect reactionrate. (ACC-1)

Journal

• Using the kinetic molecular theory and the collision theory,describe how temperature, particle size, concentration andcatalyst can be manipulated/used to increase the rate of achemical reaction. (ACC-1)

Collision Theory, Reaction Mechanisms, and Catalysts1.5 days (2 hours)

MHR Chemistry 469-477, 481-482



MHR Website



46

Outcomes





Collision Theory, Reaction Mechanisms, and Catalysts (continued)

1.5 days (2 hours)

• describe a reactionmechanism and catalyst’s rolein a chemical reaction(ACC-2)– draw and label a potential

energy diagram to show theeffect of a catalyst on the rate ofa reaction

– define, draw, and label thefollowing on a potential energydiagram for an exothermic andendothermic reaction: activationenergy, activated complex,transition state, HΔ , reactants,and products

– define reaction mechanism as aseries of elementary reactions

– identify the followingcomponents of a reactionmechanism: rate-determiningstep, reaction intermediates, andcatalysts

– write the overall reactionequation from a reactionmechanism

Students should define reaction mechanisms and show how a catalystaffects the rate of a chemical reaction by providing a differentreaction mechanism. Students could research and prepare reports oncatalysts used in commercial or industrial applications.

Students should draw and interpret potential energy diagrams forvarious reactions. Students’ interpretations should includeexothermic, endothermic, enthalpy, activation energy, activatedcomplex, reactants, products, and HΔ .

A potential energy diagram to show the effect of a catalyst on the rateof reaction allows students the opportunity to understand the role ofa catalyst on the rate of reaction. The steps of a reaction mechanismshould be given and students should be able to identify the rate-determining step, reaction intermediates, and catalysts, and to addthe steps of the overall reaction taking place to show that it equalsthe overall reaction.

When discussing the fundamentals of reaction mechanisms, studentsmight propose balanced equations for multi-step reactions (e.g., thereaction of hydrogen and bromine to form hydrogen bromide). Theactual determination of a reaction mechanism is difficult and requirestime. Students should realize that the reaction rate (fast or slow)involves many particles that must collide according to the balancedequation of a reaction mechanism step, and not the balanced overallequation for the reaction.

Students should recognize that E and ∆E are often used in potentialenergy diagrams instead of H & ∆H. The use of E and ∆E arepractical for all situations, particularly those in which the energyabsorbed/released is in a form other than heat (ex. light). However,when a reaction involves thermal energy, H and ∆H are commonlyused.

47




Paper and Pencil

• Draw and correctly label a potential energy diagram for anendothermic and exothermic reaction. Include the shape of thecurve, correct labelling for activation energy and energies ofreactants, products, and activated complex. (ACC-2)

• Given the following reaction mechanism, identify the: a) catalyst(if any), b) intermediate(s); and c) rate determining step:

HCO2H + H+ --> HCO

2H

2+ very fast

HCO2H

2+ --> HCO+ + H

2O slow

HCO --> CO + H+ fast (ACC-2)

• Given the above reaction mechanism, write the overall reactionequation and indicate if the equation is very fast, fast, or slow.

(ACC-2)

Presentation

• Research, and prepare to discuss with the class, a catalyst role in acommercial or industrial process. (ACC-2)

Journal

• Describe the difference between a catalyst and reactionintermediate. Explain how these can be identified from a reactionmechanism. (ACC-2)

Collision Theory, Reaction Mechanisms, and Catalysts (continued)

1.5 days (2 hours)

MHR Chemistry 473-483



MHR Website



48

Outcomes





• compile and organize data,using appropriate formats anddata treatments to facilitateinterpretation of the data(213-5)– compile and organize data from

a laboratory activity todemonstrate an understandingof the concept of equilibrium

• define the concept ofequilibrium as it pertains tosolutions (323-3)– describe an equilibrium system

of a solid in a saturated solutionin terms of equal rates ofdissolving and crystallizing

Students should compile and organize data from a laboratory activityto demonstrate an understanding of the concept of equilibrium .

Students might list examples of various solutions they think are inequilibrium. Students could begin with a laboratory activityinvolving the collection of data on equilibrium using a colouredsolution, two graduated cylinders, and two glass tubes of differentdiameters. The glass tubes can be used to transfer the colouredliquid between the graduated cylinders until no noticeable change involume is occurring in the cylinders (dynamic equilibrium).Verbalizing their explanations of the examples could help with theirunderstanding of how equilibrium is established. This is an idealopportunity for students to use graphing technology such as the TI-83 graphing calculator. Students could enter the data and have thecalculator plot the graphs of “volume vs transfer” for both theforward and reverse reactions. The graphs illustrating the changesoccurring during the forward and reverse reactions, as a result of theconsumption of reactant and the production of product, can be viewin the same window with the TI-83 calculator. Viewing both graphssimultaneously will allow students to visually identify equilibriumconditions and deepen their knowledge and understanding of theconcept of equilibrium.

Students should define equilibrium. Students should describe anequilibrium system of a solid in a saturated solution in terms of equalrates of dissolving and crystallizing. To assist in their description,they could draw a diagram illustrating solute particles entering andleaving the solution phase.

Students should compare the rate of solvation to the rate ofdesolvation for unsaturated solutions and for saturated solutioncontaining excess solute. The concept of “dynamic equilibrium”should be discussed. Although the dynamic equilibrium cannot beseen with the naked eye, students can relate to the shape of thecrystals of excess solute as they change over time since solvation anddesolvation occur simultaneously.

Chemical Equilibrium7 days (8.5 hours)

49




Performance

• Collect and graph data from an activity involving equilibrium.(213-5, 323-3)

Journal

• How are solubility and equilibrium related? (323-4)• What is the general meaning of dynamic? What is meant by

dynamic equilibrium? Give examples. (323-3, 213-5)

• Is this instruction chemically correct: “Add 5 grams of sugar toyour tea/coffee/lemonade, and stir until the sugar stopsdissolving?” Explain. (323-3)

Paper and Pencil

• Describe what is happening in the above equilibrium situation.(213-5, 323-3)

Time

Am

ount

• A chemical equilibrium is a dynamic equilibrium in whichopposite processes are occurring at equal rates. Discuss thestatement. What would help us to infer that the amounts ofreactants and products are remaining constant at equilibrium?(114-2, 323-3)

• Prepare a short, oral presentation from the list of all the thingsyou know about equilibrium generated in class. This is anexploratory exercise. Expectations are that you are questioning,analysing, describing, and/or evaluating the structure using the

scientific principles with which are familiar. Use a KWL chart.

(214-1)

KWL ChartWhat I know:

What I want to know:

What I learned:


Expresslab “Modelling Equilibrium”


Additional Practice Problems, Chapter 13“Reversible Reactions and ChemicalEquilibrium”





MHR Website






50

Outcomes





equation

Equilibrium Table

final equilibrium concentration

change occurred

initial concentration

CO2 + H

2 → CO + H

2O

Students should be able to write equilibrium constant expressions.They should develop an understanding that solids and liquids are notincluded in the equilibrium expression and that the equilibriumconstant will vary with temperature.

Students should be able to calculate, and perform calculationsinvolving, an equilibrium constant, K

c or K

eq, for chemical systems

when (a) concentrations at equilibrium are known or (b) when initialconcentrations and one equilibrium concentration are known or (c)when initial concentrations and equilibrium constant are known.These problem may require the use of the quadratic formula;however, the use of the quadratic formula can sometimes be avoidedfor situations involving very small equilibrium constants.

Students could use a table or chart to help with problems involvingequilibrium changes. Consider the problem: What is the K

c value for

the following reaction at equilibrium, at 25°C?

[ ] 22 3

43

43

H CO 3.3 10 M

HCO 1.19 10 M

H O 1.19 10 M

−

− −

+ −

= ×

⎡ ⎤ = ×⎣ ⎦⎡ ⎤ = ×⎣ ⎦

H2CO

3(aq) + H

2O(l) ⎯⎯→←⎯⎯ H

3O+(aq) + HCO

3–(aq)

When solving this Kc problem using H

2CO

3 , students could list

what they know, including the concentrations and what they want tofind. Students should write the K

c expression, substitute values into

the expression, and solve it.

Students should be able to solve Kc problems involving the initial

concentrations, the changes that occur in each substance, and theresulting equilibrium concentrations. They might use a chart like theone pictured below to organize their data.

Sample problem: What is the equilibrium concentration of this

reaction: CO2(g) + H

2(g) ⎯⎯→←⎯⎯ CO(g) + H

2O(g)?

• develop an implementappropriate samplingprocedures for equilibriumexpressions (213-1, 212-9)– write equilibrium constant

expressions– calculate equilibrium constant,

Kc or K

eq, for chemical systems

when concentrations atequilibrium are known

– perform Kc calculations

involving the initialconcentrations, the changes thatoccur in each substance, and theresulting equilibriumconcentrations

– predict the favourability ofreactant or products in areversible reaction, on the basisof the magnitude of theequilibrium constant


51




Paper and Pencil

• Benzoic acid is used in food preparation. It is slightly soluble. TheK

c for the reaction below is 6.30 × 10-5 at 25°C. [C

6H

5COOH] is

0.020 M.

The reaction is C5H

5COOH ⎯⎯→←⎯⎯ H

3O+ + C

6H

5COO–. What are

the concentrations of [H3O+] and [C

6H

5COO-]? (212-9)

• What does the Kc value of this reaction tell you about which side

is favoured, if any? (212-9)• Write an equilibrium constant expression for

CO2(g) + H

2(g) ⎯⎯→←⎯⎯ H

2O(g) + CO(g) K

c = 1.57 (212-9)

Performance

• Perform an experiment to determining the value of theequilibrium constant for a system in equilibrium. (212-9, 213-1)


Investigation 13-A “Measuring anEquilibrium Constant”







MHR Website






52

Outcomes





Type ofReaction

ReactantConcentrationon Increases

ProductRemoved

PressureIncreases

gaseous

Stress Factors Effect on Equilibrium Reactions

TemperatureIncreases

• explain how different factorsaffect solubility, using theconcept of equilibrium(323-5)– use Le Châtelier’s Principle to

determine how theconcentrations of reactants andproducts change after a changeof temperature, pressure,volume or concentrations isimposed on a system atequilibrium

– explain how a catalyst and thesurface area have an effect onthe time it takes to reachequilibrium

• explain the roles of evidence,theories, and paradigms in LeChâtelier’s Principle (114-2)– perform an experiment

involving Le Châtelier’sPrinciple to explore how stressaffects equilibrium and apply LeChâtelier’s Principle to thechanges made to this system atequilibrium

Students should use Le Châtelier’s Principle to determine how theconcentrations of reactants and products change after a change isimposed on a system at equilibrium. Students should explain how acatalyst and the surface area have an effect on the time it takes toreach equilibrium even though these do not cause the equilibrium toshift.

It is a common misconception that a change in pressure will alwaysaffect an equilibrium. An unequal number of gaseous particle in thereactants and products are required for a change in equilibrium to bepossible. It should also be noted that a change in pressure (constantvolume) as the result of the addition of a gas to the reaction vesselwill not shift the equilibrium if the gas is not involved in theequilibrium system (gas is not a reactant or product).

Students should perform an experiment involving Le Châtelier’sPrinciple to explore how stress does affect equilibrium. Studentsshould apply Le Châtelier principle to various changes made to asystem at equilibrium. Organizing their observations in a table, likethe example below, might be helpful.


53




Performance

• What happens when carbonated water is made? Open a bottle ofsoda pop and explain what you see. Write a chemical equation whenequilibrium is reached between CO

2(aq) and H

2O(l) to form

H2CO

3(aq) when the container is open. Use Le Chatelier’s

principle to explain your observations. (114-2, 323-5)

Paper and Pencil

• In which direction will the equilibrium be shifted by an increasein (1) the concentration of O

2, (2) pressure, and (3) temperature

in each of the following reactions: (323-5)

a) 2CO(g) + O2(g) ⎯⎯→←⎯⎯ 2CO

2(g) + heat

b) 2SO2(g) + O

2(g) ⎯⎯→←⎯⎯ 2SO

3(g) + heat

c) N2(g) + O

2(g) + heat ⎯⎯→←⎯⎯ 2NO(g)

• List the factors that can disturb an equilibrium system. (323-5)• Why does removing a product from an equilibrium system help

to produce maximum yield of that product? Refer to this

example: N2(g) + 3H

2(g) ⎯⎯→←⎯⎯ 2NH

3(g) + heat (114-2, 323-5)


Investigation 13-B “PerturbingEquilibrium”







MHR Website






54

Outcomes





• analyse and describe exampleswhere scientificunderstanding was enhancedor revised as a result of theinvention of a technology(116-2)

Students should conduct research on how our ideas of solutions andequilibrium have changed over time. Examples might include theHaber process, scuba diving, or high altitude training. Studentsshould explain how scientific knowledge increased as a result ofequilibrium evidence and theories being applied to everydaytechnologies.

Students could analyse an industrial example by discussing how thetechnology that was developed was based on scientificunderstanding. The factors that control the position of a chemicalequilibrium might be explored. For example, when a chemical ismanufactured, the chemists and chemical engineers in charge ofproduction want to choose conditions that favour the desiredproduct as much as possible. They want the equilibrium to go to theright. Teachers could introduce the Haber process, N

2(g) + 3H

2(g)

→ 2NH3(g) + heat.

Ask questions about the process: “How would increasing the pressureof the reaction to produce ammonia affect the ammonia yield?” and“How would increasing the reaction temperature affect the amountof ammonia produced in this exothermic reaction?” The optimumconditions for the Haber process could be outlined.

Students could analyse and describe one of the following situationsusing their understanding of equilibrium: limestone caves, watersofteners and hard water, climatizing to high altitudes, andhemoglobin.

• analyse and describe exampleswhere technologies weredeveloped based on scientificunderstanding (116-4)


55




Paper and Pencil

• Design a water softener. How would you deal with the problem ofhard water? (116-4, 116-2)

• Research the development of modern instruments’ effect on thepurification of drinking water. (116-4)

• In the early 1900s an endothermic process was demonstrated byBirkeland and Eyde for fixing nitrogen by passing air through a high-temperature electric arc. If a cheap electric power were available, itpromised to be a rival of the Haber-Borsch process.

N2(g) + O

2(g) ⎯⎯→←⎯⎯ 2NO(g) HΔ =+43.2kJ

According to Le Châtelier’s principle, how could the yield of NObe increased? Explain. (116-2, 116-4)

MHR Chemistry, 525, 530-534

Chemistry Bulletin “Le Chatelier’sPrinciple Beyond Chemistry”

Careers in Chemistry “Anesthesiology: ACareer in Pain Management”

MHR Website




56

ACIDS AND BASES


Introduction

Acids and Bases (20.5 days, 25 hours)

Focus and Context

Acids and bases have an effect on aqueous systems. Acid-base systemsinvolve proton transfer and are described quantitatively. Students willbe encouraged to value the role of precise observation and carefulexperimentation while looking at safe handling, storage, and disposalof chemicals. There are several ways of defining acids and bases.

Problem solving and decision making are used throughout this unit.Student laboratory skills will be developed. Teachers could provideexamples of products and processes that use knowledge of acids andbases. Emphasis through WHMIS could also be placed on handlingthese chemicals. There are many opportunities to discuss therelationships among science, technology, society, and theenvironment in this acid-base chemistry unit.


In Science 421A, students will have studied writing formulas andbalancing equations and be introduced to acid-base concepts.Students will have studied moles and stoichiometric calculations inChemistry 521A. The nature of solutions and expressing solutionconcentration will be addressed in Chemistry 621A before this acidsand bases unit.

57

ACIDS AND BASES




Curriculum Outcomes


114-2 explain the roles of evidence,theories, and paradigms in thedevelopment of scientific knowledge

114-9 explain the importance ofcommunicating the results of ascientific or technological endeavour,using appropriate language andconventions

115-7 explain how scientificknowledge evolves as new evidencecomes to light and as laws and theoriesare tested and subsequently restricted,revised, or replaced

Relationships Between

Science and Technology

116-2 analyse and describe exampleswhere scientific understanding wasenhanced or revised as a result of theinvention of a technology

Social and EnvironmentalContexts of Science andTechnology

117-2 analyse society’s influence onscientific and technological endeavours

117-7 identify and describe science-and technology-based careers related tothe science they are studying

118-6 construct arguments to supporta decision or judgment, using examplesand evidence and recognizing variousperspectives


212-4 state a prediction and ahypothesis based on available evidenceand background information

212-8 evaluate and select appropriateinstruments for collecting evidence andappropriate processes for problemsolving, inquiring, and decision making


213-3 use instruments effectively andaccurately for collecting data

213-8 select and use apparatus andmaterial safely

213-9 demonstrate a knowledge ofWHMIS standards by selecting andapplying proper techniques forhandling and disposing of lab materials


214-1 describe and apply classificationsystems and nomenclature used in thesciences

214-4 identify a line of best fit on ascatter plot and interpolate orextrapolate based on the line of best fit

214-5 interpret patterns and trends indata, and infer or calculate linear andnon-linear relationships amongvariables

214-17 identify new questions orproblems that arise from what waslearned


215-2 select and use appropriatenumeric, symbolic, graphical, andlinguistic modes of representation tocommunicate ideas, plans, and results

215-6 work co-operatively with teammembers to develop and carry out aplan, and troubleshoot problems asthey arise

320-1 describe various acid-basedefinitions up to the Brønsted-Lowrydefinition

320-2 predict products of acid-basereactions

320-3 compare strong and weak acidsand bases using the concept ofequilibrium

320-4 calculate the pH of an acid or abase given its concentration, and viceversa

320-5 describe the interactionsbetween H+ ions and OH- ions usingLe Châtelier’s principle

320-6 determine the concentration ofan acid or base solution usingstoichiometry

320-7 explain how acid-base indicatorsfunction

58

Outcomes

ACIDS AND BASES




Properties and Definitions of Acids and Bases2.5 days (3 hours)

• describe and applyclassification systems andnomenclature used in acidsand bases (214-1)– define acids and bases

operationally in terms of theireffect on pH, taste, reactionswith metals, reactions with eachother, conductivity, andindicators

From various activities, students should define acids and basesoperationally in terms of their effect on pH, taste, reactions withmetals, neutralization reactions with each other, conductivity, andindicators.

Teachers could begin by having students write a list of all the thingsthey know about acids and bases in their journals. Students couldcontribute these to a class list by suggesting things they might want toknow about acids. Students should conduct an experiment inattempt to classify various chemicals into groups based on theirproperties using the following tests: conductivity, litmus paper, pHpaper, Mg ribbon, and CaCO

3 chips. After summarizing the results

in a table, students could identify each solution as acidic, basic,neutral ionic, or neutral molecular.

Students could examine the labels on various packaged food todetermine which chemicals are present. They could then look up theformulas and/or do tests to determine which are acidic, basic, orneutral. To do this, the students could use the Handbook for Physicsand Chemistry, The Merck Index, or Internet sites.

Students should define and identify Arrhenius acids and writeionization equations for the behaviour of Arrhenius acids in watersuch as: HNO

3(l) + H

2O(l) → H

3O+(aq) + NO

3–(aq).

Students should define and identify Arrhenius bases. Studentsshould understand that an Arrhenius base must ionize to producehydroxide ions in aqueous solutions. Students should writedissociation equations for the behaviour of these bases such as thefollowing:

NaOH(s) → Na+(aq) + OH– (aq)

Ca(OH)2(s) → Ca2+(aq) + 2OH–(aq)

Ionization of weak bases such as NH3 should be included in

discussion using equations.

• describe various acid-basedefinitions up to theBrønsted-Lowry definition(320-1)– define and identify Arrhenius

acids– write ionization equations for

the behaviour of Arrhenius acidsin water

– define and identify Arrheniusbases

– write dissociation equations forthe behaviour of Arrheniusbases

59


ACIDS AND BASES


KWL ChartWhat I know:

What I want to know:

What I learned:

Performance

• Classify, using appropriate tests, the following as an acid, a base,or neutral (neither acidic or basic):– sodium carbonate – calcium hydroxide– hydrochloric acid – ammonia– sulfuric acid – sugar(214-1, 320-1)– potassium hydroxide

Paper and Pencil

• Write an equation for the dissociation of Mg(OH)2(s). (320-1)

• Write an equation for the ionization of HClO3(aq). (320-1)

• How do you account for the brightness of the bulb when doingconductivity tests? (214-1, 320-1)

• What must be present in order for a solution to conductelectricity? (214-1, 320-1)

• Create an organizational chart that will assist in categorizing andnaming acids. (214-1)

Presentation

• Using a concept map, organize the Arrhenius and Brønsted-Lowryacids and bases definitions. (320-1)

• Prepare a short, oral presentation from the list of all the things youknow about acids and bases generated in class. This is an exploratoryexercise. Expectations are that you question, analyse, describe,and/or evaluate the structure using familiar scientific principles.Use a KWL chart. (214-1)

Performance

• Perform an experiment to observe the properties, and to developoperational definitions, of acids and bases. (214-1)

Journal

• Compare the conductivity of solutions to that of metals.(214-1, 320-1)

Properties and Definitions of Acids and Bases2.5 days (3 hours)


Investigation 14A “Observing Properties ofAcids and Bases”


Additional Practice Problems, Chapter 14“Properties of Acids and Bases”

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Properties and Definitions of Acids and Bases (continued)

2.5 days (3 hours)

• explain how acid-base theoryevolved as new evidence andlaws and theories were testedand revised, or replaced(115-7)– define a Brønsted-Lowry acid

and a Brønsted-Lowry base– interpret equations in Brønsted-

Lowry terms and identify theacid and base species

The Brønsted-Lowry acid-base theory should be introduced toaccount for non-hydroxide bases, such as a carbonate and/orhydrogen phosphate ion.

Students should interpret equations in Brønsted-Lowry terms andidentify the acid and base species. Examples should include

HCl(aq) + H2O(l) → H

3O+(aq) + Cl–(aq)

H2SO

4(l) + H

2O(l) → H

3O+(aq) + HSO

4–(aq)

Students could compare the Arrhenius and Brønsted-Lowry definitionsby using a chart to help with their organization of the information.Students should define a Brønsted-Lowry acid and a Brønsted-Lowrybase. By writing single-step and overall equations for the acid-basereactions of a substance that can donate/accept more than oneproton, students see how each species acts as an acid or base.

• explain the roles of evidence,theories, and paradigms inacid-base theories (114-2)– trace the development of acid-

base theories from the originalArrhenius definition to themodern revised Arrheniusconcept up to the Brønsted-Lowry theory

– define and identify amphotericsubstances

Students should explain how some substances helped reviseArrhenius’ theoretical definition of acids.

The development of the acid-base theories up to Brønsted-Lowryshould be traced to show how knowledge and thinking changed toexplain new observations.

Students should define and identify amphoteric substances.Examples are given below:

NH3(aq) + H

2O(l) → NH

4+ + OH–(aq)

H2O(l) + H

2O(l) → OH–(aq) + H

3O+ (aq)

HCO3

–(aq) + OH–(aq) → CO3

2–(aq) + H2O(l)

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ACIDS AND BASES


Properties and Definitions of Acids and Bases (continued)

2.5 days (3 hours)

Paper and Pencil

• Define the following: Bronsted-Lowry Acid; Bronsted-LowryBase. Provide an example of each. (115-7)

• Write an equation for the ionization of the following Bronsted-Lowry bases: NH

3; CO

32-; HPO

42-. (115-7)

• Write an equation for the ionization of the following acids:H

2SO

4,; HCl; HClO

4. (115-7)

• What characteristics make a substance amphiprotic? Give anexample. (114-2)

Journal

• Explain why NH3 is not considered a base according to the

Arrhenius definition. (114-2)

• Although the Arrhenius definition is not comprehensive, explainits importance in developing our current understanding of acidsand bases. (114-2)

MHR Chemistry, 553-558



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Acid/Base Reactions2.5 days (3 hours)

• predict products of acid-basereactions (320-2)– write chemical, ionic, and net

ionic equations specific to acid-base reactions

• identify new questions orproblems that arise from whatwas learned (214-17)– identify the Brønsted-Lowry

acid and Brønsted-Lowry basein strong acid-baseneutralization reactions

– define and identify Brønsted-Lowry conjugate acid-base pairs

Students should write chemical, ionic, and net ionic equationsspecific to acid-base reactions. Given two reactants, students shoulduse a table of acid and base strengths to predict the products by firstidentifying which reactant will act as the acid and which will act asthe base.

Consider the following reactants: HCO3

- + HPO4

2- ⇔ ?

HCO3- is a stronger acid and it will donate a proton to become

CO3

2-

HPO4

2- is a stronger base (weaker acid) and it will accept a proton tobecome H

2PO

4-

The resulting equation is: HCO3- + HPO

42- ⇔ CO

32- + H

2PO

4-

acid base c. base c. acid

Students might wonder why neutralization occurs between acids andbases. Students should identify the Brønsted-Lowry acid andBrønsted-Lowry base in strong acid-base neutralization reactions.Students should define and identify Brønsted-Lowry conjugate acid-base pairs.

H2O(l) + NH

3(aq) → NH

4+(aq) + OH–(aq)

acid + base → conjugate acid + conjugate base

Students might remember doing these various types of equations whenstudying solutions. Students might compare the net ionic equationsfrom a few reactions to look for patterns. Students could identify theproducts of an Arrhenius acid-base neutralization. The net ionicreaction should be H

3O+(aq) + OH–(aq) → 2H

2O(l).

This is a neutralization reaction. A clean-up of an acid spill, theantacid reaction in your stomach, or neutralizing the soil acidity inyour lawn could be helpful in explaining acid-base neutralizationreactions.Students should, in small groups, discuss the usefulness of acid-basereactions.

Acid-base reactions involve water, hydrogen ions, hydronium ions,and hydroxide ions. Students could compare the nature of [H+(aq)]and [H

3O+(aq)] and explain if they are the same or different.

Teachers might show, how [H3O+] is a hydrated proton.

• explain the importance ofcommunicating the results ofacid-base reactions usingappropriate language andconventions (114-9)

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ACIDS AND BASES


Acid/Base Reactions2.5 days (3 hours)

Journal

• Neutralization is a process that is controlled in lab experiments.How do you think this process works? Does it work in otherenvironments, like a lake or your stomach? (214-17, 320-2,114-9)

Paper and Pencil

• Identify which reactant is the Brønsted-Lowry acid and which isthe Brønsted-Lowry base. (320-2)

HSO4

–(aq) + H2O(l) → H

3O+(aq) + SO

42–(aq)

HCN(aq) + H2O(l) → H

3O+(aq) + CN–(aq)

• Write an equation for each of the three ionization steps wherephosphoric acid would donate three hydrogen (protons) ions.(320-2)

• Identify which of the following act as the acid and which act asthe base. Predict the products.

- HCO3

- and HF

- H2PO

42- and CO

32-

- HNO3 and H

2O (320-2)

Presentation

• Identify the acid, base, conjugate acid and conjugate base in thefollowing: H

2O(l) + NH

3(aq) ⇔ NH

4+(aq) + OH–(aq). (320-2)

• Illustrate the donation of a proton from an acid to a base usingHCl(aq) and NaOH(aq); HCl(aq) and H

2O(aq); NH

3(aq) and

H2O(aq). (320-1, 114-9)

MHR Chemistry, pp 552-558, 560-564



BLM 14-1 “Illustrating the Properties ofAcids and Bases”

Appendix E, Table E.20 “Relative Strengthof Acids and Bases” p. 850

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H+, OH–, and Le Châtelier1.5 days (2 hours)

• describe the interactionsbetween H+ ions and OH–

ions using Le Châtelier’sprinciple (320-5)– use Le Châtelier’s principle to

predict, qualitatively, shifts inacid-base equilibrium

– write the equation for, andexplain, the self-ionization ofwater

– write the equation for thereaction between water and thehydrogen ion to producehydronium ion

– identify the [H+] and [OH-]associated with acidic and basicsolutions

• analyse society’s influence onacid and base scientific andtechnological endeavours(117-2)

• construct arguments tosupport a decision usingexamples and evidence andrecognizing variousperspectives (118-6)

• identify and describe science-and technology-based careersrelated to acids and bases(117-7)

The self-ionization of water produces a system at chemicalequilibrium for which we can write an equilibrium constant forwater, Kw. Students should write the equation for, and explain, theself-ionization of water and identify it as being amphoteric. Studentsmight identify the extent of the self-ionization of water and note thatthe Kw value we use is for the equilibrium at 25°C. Students shouldunderstand that the use of a catalyst does not cause a shift in theequilibrium, and that temperature needs to be constant.

Students should write the equation for the reaction between waterand the hydrogen ion to produce a hydronium ion. Students shouldrecognize that all of the available [H+] is in the form of [H

3O+].

Students should identify the [H+] and [OH-] associated with acidicand basic solutions.

Students could perform a lab representing the reversible nature ofthe acid-base equilibrium system using an indicator, and writechemical equations representing this reversible nature. Using LeChâtelier’s principle, students could predict the colour change as aresult of an equilibrium shift when a strong acid or a strong base isadded.Students should look at society and the ways it influences scienceand technology by explaining the significance of strength andconcentration in chemical spills, in transportation of dangerousgoods, or in acid deposition. Another approach might be from ahistorical perspective: trace the development of the pH scale as anexample of the way scientists have strived to improvecommunication. Water is involved in many aspects of our lives.Students might look at various foods and chemicals in their home tosee how water might be involved with each.

An investigation of the various perspectives of food production suchas additives or genetic engineering might form the basis of a classdebate or a class decision to help support a local initiative,technology, or societal endeavour.

Students should identify careers that involve acid-base chemistry.Students could consider a career of interest to them and investigateit. Students might identify the use of acid-base chemistry in aparticular career and defend the appropriate use of specific chemicals.Examples may include careers involving consumer products such asvarious cosmetics which require a pH balance or the acidity rangerequired for enzymes to function effectively.

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ACIDS AND BASES


H+, OH–, and Le Châtelier1.5 days (2 hours)

Performance

• Perform an experiment focusing on an acid-base equilibrium usingLe Châtelier’s principle and report your findings. (320-5)

• Act out the ionization of water. (320-5)

Paper and Pencil

• Create a chart illustrating the range of [OH-] and [H3O+]

associated with acidic, basic and neutral solutions. (320-5)• Using Le Châtelier’s principle and a diagram, explain and

illustrate the shifts in equilibrium and the [H3O+] or [OH-]

resulting from the addition of acid and base. (320-5)• Describe the significance of pH in one of the following:

– the maintenance of viable aquatic and/or terrestrialenvironments

– the body fluids of living systems– the formation of various products; for example, shampoo,

cleaners(117-2, 117-7, 118-6)

Journal

• Explain how water self-ionizes. Use a diagram to illustrate theproton transfer and the resulting charges on, and structures of,the hydroxide and hydronium ions. (320-5)




Chemistry Bulletin “The Chemistry ofOven Cleaning” p. 577

Careers in Chemistry “Dangerous GoodsInspection” p. 615

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Using the Equilibrium Concept with Acids and Bases8.5 days (10 hours)

• compare strong and weakacids and bases using theconcept of equilibrium(320-3)– understand that acid and base

systems are quantitativelydescribed, using pH, pOH,[H

3O+ (aq)], [OH- (aq)], Kw,

Ka, Kb, % dissociation, andconcentration

– perform calculations todetermine any of the abovefrom empirical data

– define % dissociation, Ka andKb qualitatively and relate theirvalues to acid and base strength

– identify the values of pH andpOH associated with acidic andbasic solutions

Students should define strong and weak acids and bases. Studentsshould define % dissociation, Ka and Kb and relate their values toacid and base strength. They should identify the favorability ofreactants or products for an acid-base equilibrium based on Ka valuesprovided for reactant and product species.

Students should distinguish between the terms strong acid (or strongbase) and acidic (or basic). They should identify the values of pHand pOH associated with acidic and basic solutions.

Students should identify that the presence of [H3O+] or [OH-] from

an added strong, or reasonably strong acid or base will not beaffected to any significant extent by the self-ionization reaction forwater which avoids having to account for the [H

3O+] or [OH-] ions

produced.

Problem solving using Kw might be done here. Students could solvefor either [H

3O+] or [OH-] using Kw at 25°C. Additional problems

could include the determination of the molarity, M, of these ions.For example: calculate the [H+] or [H

3O+] if 5.0 g of NaOH is

dissolved in 200 mL solution.

Students should write appropriate Ka and Kb equilibrium constantexpression from the equations, knowing that water, as a liquid, isomitted in the equilibrium expression. For example, the acetic acidin vinegar in water:

CH3COOH(aq) + H

2O(l) → H

3O+(aq) + CH

3COO–(aq)

Ka = [H3O+][CH

3COO-]

[CH3COOH]

Students should calculate the value of Ka or an equilibriumconcentration given all other values for the equilibrium expression.An ICE (Initial-Change-Equilibrium) chart is a helpful method oforganizing data and making the connection between reactant andproduct species.

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ACIDS AND BASES


Using the Equilibrium Concept with Acids and Bases8.5 days (10 hours)

Paper and Pencil

• Create a chart illustrating the range of pH and pOH associatedwith acidic, basic and neutral solutions. (320-3)

• Write the equilibrium constant expression for the following:HClO and CH

3COOH (acids)

HS- and CH3NH

2 (bases) (320-3)

• The pH of a 0.072 mol/L solution of benzoic acid, C6H

5COOH

is 2.68. Calculate the numerical value of the Ka for this acid.(320-3)

• What is the pH of a solution formed by mixing 100 mL of0.150 mol/L HCl(aq) with 150 mL of 0.0900 mol/L NaOH(aq)?(320-3)

• HF (Ka = 6.6 × 10–4) and HCN (Ka = 6.2 × 10–10) are two weakacids that appear in this equilibrium:HCN(aq) + F–(aq) ⇔ HF(aq) + CN–(aq)

– Use this information to explain qualitatively which equilibriumdirection is favoured. Which acts like an acid and which actslike a base?

– Using Ka expressions and the Ka values provided, calculate thenumerical value of the equilibrium constant for the reaction.(320-3)

Journal

• Describe the relationship between the Ka value of an acid and thepH of its solution. (320-3)

• Describe why it would it be impractical to include theconcentration of H

2O

(l) in the acid or base dissociation constant

expression. (320-3)

MHR Chemistry, pp. 560-578 582-595



Additional Practice Problems, Chapter 15“Acid-Base Equilibria and Reactions”

Additional Investigation Unit 6B“Working with indicators”


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Using the Equilibrium Concept with Acids and Bases (continued)

8.5 days (10 hours)

• compare strong and weakacids and bases using theconcept of equilibrium(320-3) (continued)– understand that acid and base

systems are quantitativelydescribed, using pH, pOH,[H

3O+ (aq)], [OH- (aq)], Kw,

Ka, Kb, % dissociation, andconcentration

– perform calculations todetermine any of the abovefrom empirical data

– perform calculations ofequilibrium concentrationsgiven initial concentration andK value for which the quadraticequation may be used

– perform calculations ofequilibrium concentrationsgiven [H+] or pH and the Kvalue

For calculations involving the equilibrium constant expression inwhich calculations must be performed prior to substituting valuesinto the expression, group discussion of problem solving strategieswould help students to better understand the relationships betweenreactant and product species, initially and during equilibrium.

An ICE (Initial-Change-Equilibrium)chart is a helpful method oforganizing data and making the connection between reactant andproduct species.

CH3COOH + H

2O ⇔ CH

3COO- + H

3O+

I 0.100M 0 ~0

C -x x x .

E 0.100-x x x

0.100 ( if “x” is negligible)

The above ICE table involves the calculation of concentration of allequilibrium species given the Ka and initial concentration. Thequadratic equation may be required to solve for “x”; however, thefollowing guide may be used for situations in which the value of Ka(or Kb) is small enough to assume that amount of acid (or base)dissociated, “x”, is negligible in relation to the initial concentration ofacid (or base). This simplifies the calculation by eliminating theneed to use the quadratic equation.

If [HA] > 500, the change “x” in initial concentration is negligible. Ka

If [HA] < 500, the change “x” in initial concentration is not Ka negligible. The quadratic equation will be required.

Other methods may also be used to determine if the change in initialconcentration is negligible. One method is to assume the change isnegligible and use the resulting equilibrium concentrations tocalculate the value of Ka (or Kb). If the calculated value is less than5% different from the given value, the assumption made wasacceptable; otherwise, the assumption cannot be made.

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ACIDS AND BASES


MHR Chemistry, pp. 560-578 582-595





MHR Website



Paper and Pencil

• Calculate the equilibrium concentrations of all species atequilibrium if the pH of a 0.020M solution of C

6H

5COOH is

2.96. (320-3, 320-4)• Calculate the value of Ka for C

6H

5COOH if the pH of a 0.020M

solution of C6H

5COOH is 2.96. (320-3)

• Calculate the equilibrium concentrations of all species atequilibrium given the following information:i. [C

6H

5COOH]

initial = 0.100M; Ka = 6.3 x 10-5

ii. [CH3COOH]

initial = 0.100M; Ka = 1.8 x 10-5

iii. [HF]initial

= 0.100M; Ka = 6.3 x 10-4 (320-3)

Journal

• Explain why in certain situations that an assumption can bemade that the difference between the initial and equilibriumconcentrations of the reactant species can be considerednegligible. (320-3)


8.5 days (10 hours)

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Students should define the pH and pOH of solutions. Studentsshould define the relationships among [H

3O+], [OH-], pH, and

pOH. Students should perform calculations where they makeconversions among these. Solving problems could be practised insmall groups.

Students should calculate [H3O+] given the concentration of strong

acids. Students should calculate [OH-] given concentrations of strongbases. Students should calculate the pH or pOH of a dilutedsolution. Connection should be again made between thedissociation constant and pH where students could calculate the pHof a solution given the initial concentration of a weak acid and Ka.

In groups of two, students can randomly choose a value for thehydronium ion concentration of a monoprotic strong acid. Onestudent in the group can calculate the pH directly while the otherstudent can calculate the pH indirectly by first calculating the [OH-]and then pOH. They can then compare results and repeat theactivity by reversing roles and choosing another concentration.

Students should demonstrate an understand of the various benefits ofhaving a pH scale to represent hydronium ion concentration. ThepH scale is the method used to express hydronium ion concentrationon labels of consumer products. Concentrations expressed inscientific notation with negative exponents and a range in values inthe order of 1014 is not appealing to the consumer, and is often notunderstood.


8.5 days (10 hours)

• calculate the pH of an acid orbase given its concentration,and vice versa (320-4)

– calculate pH given theconcentration of a strong acid orstrong base

– calculate pH given theconcentration of a weak acid orweak base along with thecorresponding dissociationconstant

– calculate pH from pOH, [H+],[OH-], and vice-versa

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ACIDS AND BASES


Journal

• How can a pH be negative? (320-4, 212-4)• Explain why a 0.10 M HCl solution has a low pH. (320-4)• How does the Ka value of an acid relate to the pH of its solution?

(320-4)

Paper and Pencil

• How are acidity and pH related? (320-4)

• What is the pH of a 0.025 M NaOH solution? (320-4)• The pH of the rain precipitation near a power plant is 4.35.

What is the [OH-] in this precipitation? (320-4)• What is the pH of a 0.025 M solution of Ba(OH)

2? (320-4)

• What is the pH of a 0.02 M benzoic acid solution if Ka = 6.5 ×10-5 . (320-4)

Performance

• Perform an experiment to determine the effect of dilution on thepH of an acid. (320-4)


8.5 days (10 hours)

MHR Chemistry, pp. x-xiii, 567-578pp 585-595




Investigation 14-B “The Effect ofDilution on pH of an Acid”

BLM 14-2 “pH Calculations”


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Acid/Base Titrations5.5 days (7 hours)

• determine the concentrationof an acid or base solutionusing stoichiometry (320-6)

• select and use apparatus andmaterial safely (213-8)

• use instruments effectivelyand accurately for collectingtitration data (213-3)

• interpret patterns and trendsin data, and infer or calculaterelationships among variablesfrom titration labs (214-5)

• work co-operatively withteam members to develop andcarry out a plan for a titrationlab, and troubleshootproblems as they arise (215-6)

• evaluate and selectappropriate instruments forcollecting evidence andappropriate processes fortitrations (212-8)

Students should perform stoichiometric titration calculations whereone of the following four quantities is to be determined given theother three: molarity of acid; molarity of base; volume of acid; andvolume of base. This activity could help with lab questions andstoichiometry problems.

Students should perform a minimum of two titration experimentswhich may involve: determining an unknown concentration;collecting data to create a titration curve; and determining a value ofKa.

Students’ selection of apparatus should be appropriate for use in anacid-base titration. Students might have seen the apparatus thatcould be used in various titration experiments. Teachers could choosefrom titration labs such as HCl and NaOH, CH

3COOH and

NaOH, or the effectiveness of various antacid tablets. Studentsshould know the terminology involved with titrations: pipette,buret, endpoint, equivalence point, standard solution, and indicator.Students should differentiate between indicator endpoint andequivalence (stoichiometric) point. Planning a lab requirescommunication and collaboration with the student’s lab partner.From teacher information and their own, students could organize thesteps that are required in the process for a titration lab.

• select and use appropriatenumeric, symbolic, graphical,and linguistic modes ofrepresentation tocommunicate ideas, titrations,and results (215-2)

Reporting of lab results should be done. Students could present theirlab results so that their understanding of pH and titrations is clearlyshown. Students might use graphs, videos, charts, a computer,activities, or oral reports to consolidate their titration information.

• demonstrate a knowledge ofWHMIS standards byselecting proper techniquesfor handling and disposing oflab materials (213-9)

Students should recognize the usefulness of WHMIS standards.Students could do a project on WHMIS standards. In the lab,students could be shown apparatus that might be used in a futureacid base titration experiment and decide on the safe and proper useof the apparatus. Students should be shown the proper use of theequipment. Students could be asked to think about how they wouldsafely dispose of acids and bases. Then, information collected couldhelp students know how to use apparatus safely. The proper way tohandle and dispose of acids and bases is part of WHMIS knowledgethat is useful in the laboratory, workplace, and home.

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ACIDS AND BASES


Acid/Base Titrations5.5 days (7 hours)

Informal Observation / Performance

• Watch the use of the equipment used in an acid-base titration andpractise the safe and efficient use of the equipment. (213-8, 213-9)

• Design an experiment to test the neutralization effectiveness ofvarious brands of antacid. Show your procedure to your teacherfor approval. Include all safety procedures and cautions. Write anadvertisement for the antacid you judge to be the most effective.If the experiment is performed, then include data from yourexperiments in your ad. (320-6, 213-8, 215-2, 213-3, 214-5,215-6, 212-8)

• Show the proper care and maintenance of a buret. (213-8)

Journal

• A NaOH solution has a pH of 10.5. What volume of 0.01 MHCl would be required to titrate this solution to the equivalencepoint? What additional information is required to solve thisproblem? (320-6, 215-2, 215-6)

• Explain, qualitatively and quantitatively, the concept of titration.(213-3, 215-2, 320-6)

Paper and Pencil

• Why is a buret, not a graduated cylinder, used in a titration?(213-3)

• Wally and Bobby Lou use 2.00 g of a solid potassium hydrogensulfate, to titrate with 34.7 mL of a NaOH solution. The molarmass of the acid is 204.2 g/mol. What is the molarity of theNaOH solution? (320-6, 215-6)

• Nadine and Rob titrated 35.0 mL of liquid drain cleaner,containing NaOH, with 50.1 mL of 0.41 M HCl to reach theequivalence point. What is the concentration of the base in thecleaner? Would a computer analysis be helpful here? Explain.(320-6, 215-6)

• Karla and Desmond want to find the molarity of a lactic acidsolution. A 150.0 mL sample of lactic acid, CH

3CHOHCOOH,

is titrated with 125 mL of 0.75 M NaOH. What is the molarityof the acid sample? (215-6, 320-6, 215-2)

• Examine diagrams of apparatus used in titrations and describe theuse of each. Examples should include the buret and Erlemeyerflask. (213-8, 213-9)




Investigation 15-A “The Concentration ofAcetic Acid in Vinegar”

Investigation 15-B “Ka of Acetic Acid”

BLM 15-1 “Determining theConcentration of an Acid”

BLM 15-2 “Titration Procedure”

Appendix E, Table E.19 “Endpointindicators” p. 849

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Students could explain a titration graph involving a polybasic specieswith a strong acid (for example, hydrochloric acid, a strong acid withsodium carbonate). Students should explain the results of a titrationgraph involving a polyprotic species with a strong base (for example,phosphoric acid with sodium hydroxide). Students should explainthe pH at the equivalence point when strong acids are mixed withweak bases and vice versa. Teachers might mention salt hydrolysishere to help explain titration curves, in particular when the pH atthe equivalence point does not equal 7.

• explain how acid-baseindicators function (320-7)– differentiate between the terms

endpoint and equivalence point– choose appropriate indicators for

acid-base titrations

• analyse and describe exampleswhere acid-baseunderstanding was enhancedas a result of using titrationcurves (116-2)– qualitatively sketch and

interpret titration curves

Students should compare the qualitative term, endpoint, with thequantitative term, equivalence point. Students should identify thepH of a solution using indicators. Students should chooseappropriate acid-base indicators given the pH at the equivalencepoint and a table of effective pH ranges for various acid-baseindicators.

Students could perform an experiment to determine the pH ofvarious acids and bases using indicators.

Acid/Base Titrations (continued)

5.5 days (7 hours)

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ACIDS AND BASES


Performance

• Your teacher will give you a solution to test for pH usingindicators. Describe exactly how you would test the solution.Show your plan to your teacher. If approved, conduct the test andreport the results. (213-8, 215-2, 213-3, 214-5, 215-6, 212-8,320-7)

Paper and Pencil

• How is the colour change of an indicator related to pH? (320-7)• What is key in choosing an appropriate indicator? (320-7, 116-2)• What indicators could you use for a titration involving a solution

of HCl, a strong acid, and a solution of Na2CO

3, a weak base?

(320-7, 116-2)• What is equivalence point? endpoint? Why is it important that

both occur at approximately the same pH in a titration? (320-7,116-2)

• If a titration between a weak acid and a strong base has anequivalence point pH of 9.5, which indicators could be used todetect the equivalence point of the titration? (320-7, 116-2)

• What is the determining factor when selecting an indicator to usein a titration? (320-7, 116-2)

• For the following titrations, select the best indicator from thesechoices: bromophenol blue, bromothymol blue, phenol red.– HCOOH, formic acid, with NaOH– HCl with potassium hydroxide– ammonia with hydrochloric acid(116-2, 320-7)

• Which indicators would work best for a titration with– an endpoint at a pH of 4.0– a weak base with a strong acidUse an indicator chart as a reference. Justify your choice.(116-2, 320-7)

Journal

• In the titration of a weak acid with a strong base, explain if thepH at the equivalence point is greater than, less than, or equal to7. (116-2, 215-2)

• Why is it best to titrate with a dilute solution? (116-2, 320-7)


5.5 days (7 hours)




Additional Investigation Unit 6B“Working with Indicators”


MHR Website





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Outcomes

ACIDS AND BASES




• identify a line/curve of bestfit on a scatter plot andinterpolate and extrapolatebased on the line of best fit(214-4)– interpret, interpolate and

extrapolate data from a titrationcurve

– graph sample data collectedfrom a titration experiment ordata provided by their teacher

• state a prediction andhypothesis based on availableevidence and backgroundinformation (212-4)

Students should interpret, interpolate and extrapolate data from atitration curve of an acid-base neutralization reaction.

Students could graph sample data collected from one of the titrationexperiments or data provided by their teacher. This is an idealopportunity for students to use graphing technology such as the TI-83 graphing calculator. The trace feature on the calculator could beused to identify the pH value at which the equivalence point isreached. One valuable feature of the graphing calculator is thatseveral graphs can be placed on the same view screen. The benefit ofthis multiple view feature is that students can observe and develop anunderstanding of the significance of the shape of the curve in relationto the strength of the acid and base titrated.

Using various examples, students should predict acid-base strengthof various foods based on their knowledge. Students could look atvarious foods or liquids to predict the strength of the acid in theseproducts. Some substances might be milk, red cabbage, coffee, pop,apple juice, and liquid soap. Students might prepare a chart to showtheir predictions, and, later, they could find the pH and comparetheir predictions with actual results.

Substance Prediction Strength pH Value

milk

red cabbage

basic low 6.6

Predict Whether Acidic or Basic and Strength


5.5 days (7 hours)

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ACIDS AND BASES


Performance

• Create a poster illustrating both proper and improper acid-basedisposal. (213-9)

• Predict and test the pH of various foods. Use the operationaldefinitions you had created at the beginning of this unit topredict the pH and use pH paper or indicators to test pH levels.Record your predictions and results in a chart. (212-4)

Paper and Pencil

• Collect data from an acid-base titration experiment and plot acurve of pH vs[ ]. (214-4)

• Interpret the data from an acid-base curve by identifying: theequivalence point; pH at the equivalence point; the nature of theacid and base species (strong or weak). (214-4, 212-4)


5.5 days (7 hours)




Investigation 15-A “the Concentration ofAcetic Acid in Vinegar”

Investigation 15-B “Ka of Acetic Acid”

BLM 15-1 “Determining theConcentration of an Acid”

BLM 15-2 “Titration Procedure”


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ELECTROCHEMISTRY


Introduction

Electrochemistry (17.5 days, 21 hours)

Focus and Context


Students will have studied the mole and electronegativity in Chemistry521A. Solutions, ionization, and chemical equilibrium inChemistry 621A should be completed before beginningElectrochemistry.

This unit builds on concepts dealing with electric forces, matter andenergy in chemical change, and quantitative relationships inchemical changes. Energy is involved in electrochemical changes.Problem solving and decision making in this unit will be helpful increating an interest in the application of technology. Students shouldinvestigate, through laboratory work and relevant problems, the waysin which science and technology advanced in relation to each other.The oxidation-reduction reactions that occur in everyday life, theproducts and processes used in industry, or the relationship of globalenvironmental problems to oxidation-reduction reactions could beinvestigated.

Matter is electrical in nature and some of its most importantparticles—electrons, protons, and ions—carry electric charge. Whenan electrical potential is applied between electrodes placed in asolution of ions, ions migrate to oppositely charged electrodes andchemical reactions take place. Quantitative aspects of this electrolysisare important in analytical chemistry and the chemical industry.

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ELECTROCHEMISTRY




Curriculum Outcomes


115-1 distinguish betweenscientific questions andtechnological problems

115-5 analyse why and how aparticular technology was developedand improved over time


116-6 describe and evaluate thedesign of technological solutionsand the way they function, usingscientific principles

116-7 analyse natural andtechnological systems to interpretand explain their structure anddynamics


118-4 evaluate the design of atechnology and the way it functionson the basis of a variety of criteriathat they have identified themselves


212-1 identify questions toinvestigate that arise from practicalproblems and issues

212-2 define and delimit problemsto facilitate investigation

212-7 formulate operationaldefinitions of major variables


213-2 carry out procedurescontrolling the major variables andadapting or extending procedureswhere required

212-3 design an experimentidentifying and controlling majorvariables

213-8 select and use apparatus andmaterials safely


214-7 compare theoretical andempirical values and account fordiscrepancies

214-8 evaluate the relevance,reliability, and adequacy of data anddata collection methods

214-14 construct and test aprototype of a devise or system andtroubleshoot problems as they arise

214-16 evaluate a personallydesigned and constructed device onthe basis of criteria they havedeveloped themselves

214-18 identify and evaluatepotential applications of findings


215-7 evaluate individual and groupprocesses used in planning,problem solving and decisionmaking, and completing a task

322-1 define oxidation andreduction experimentally andtheoretically

322-2 write and balance halfreactions and net reactions

322-3 compare oxidation-reductionreactions with other kinds ofreactions

322-4 illustrate and label the partsof electrochemical and electrolyticcells and explain how they work

322-5 predict whether oxidation-reduction reactions arespontaneous based on theirreduction potentials

322-6 predict the voltage of variouselectrochemical cells

322-7 compare electrochemicaland electrolytic cells in terms ofenergy efficiency, electron flow/transfer and chemical change

322-8 explain the processes ofelectrolysis and electroplating

322-9 explain how electrical energyis produced in a hydrogen fuel cell

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Outcomes

ELECTROCHEMISTRY




Oxidation and Reduction2.5 days (3 hours)

• identify questions toinvestigate that arise frompractical problems and issueson redox (212-1)

• distinguish between scientificquestions and technologicalproblems (115-1)

• define oxidation andreduction experimentally andtheoretically (322-1 )– define the terms: oxidation-

reduction, oxidizing agent,reducing agent, oxidationnumber, and half-reactionequations and an oxidation-reduction (redox) reaction

– identify electron transfer inredox equations

– perform a lab experiment toobserve a redox reaction

– identify the oxidizing andreducing agents, the substanceoxidized and the substancereduced in a redox equation

– use oxidation number rules tofind the oxidation numbers ofthe atoms in molecules or ions

– write half-reaction equationsfrom their lab results

Students should identify questions about oxidation and reduction toinvestigate or talk about. In small groups, students might begin bylisting things they already know or think they know aboutelectrochemistry. As a class, a list could be generated and questionsabout electrochemistry could be posed. Suggestions might includethe components of various types of batteries or what happens wheniron corrodes or how electroplating occurs.

Students should distinguish between scientific questions andtechnological problems that involve oxidation and reductionsituations, for example, “What is an electrochemical cell?” and “Howcan a metal be protected from corrosion?”.

Students should define the terms: oxidation-reduction, oxidizingagent, reducing agent, oxidation number, half-reaction equations,and an oxidation-reduction (redox) reaction. Using oxidationnumber rules, students should find the oxidation numbers of theatoms in the molecules or ions. Teachers should provide examples ofhow Lewis structures can be used to identify oxidation numbers.Students could observe a zinc nail or strip in copper (II) sulfatesolution, represented by the equation: Zn + Cu2+ → Zn2+ + Cu.Discussion might be initiated by the following statement: “The zincis said to undergo oxidation because its’ oxidation state increasesfrom 0 to +2; the copper is said to undergo reduction because itsoxidation state decreases from +2 to 0.”

Students should identify electron transfer in equations likeZn → Zn2+ + 2e– and Cu2+ + 2e– → Cu

These are half-reactions. Oxidation (loss of electrons) and reduction(gain of electrons) do not occur separately. Copper ions could not bereduced without a source of electrons, and zinc, when oxidized,needs another substance to take the electrons that are given up. Theoxidizing agent, Cu2+, is reduced, and Zn, the reducing agent, isoxidized in this oxidation-reduction reaction. Other examples couldbe provided to allow students to identify the substances oxidized andreduced as well as the oxidizing and reducing agents.

Students should perform lab experiments to observe a redox reaction,such as AgNO

3 and Cu. They could then write equations for the

reaction, describe their observations, analyse the results, and identifythe oxidizing and reducing agents. “OIL RIG” is a mnemonic devicethat relates to redox reactions: “Oxidation Involves Loss, ReductionInvolves Gain.” LEO (Loss Electrons Oxidation) the lion says GER(Gain Electron Reduction) is another common mnemonic device.

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ELECTROCHEMISTRY


Oxidation and Reduction2.5 days (3 hours)

Performance

• Perform an experiment involving redox reactions. Write chemicalequations, net ionic equations, and half reactions for each reactionand, for each reaction, identify the following: species oxidized,species reduced, oxidizing agent, and reducing agent . (322-1)

• From a given list of redox reactions, determine the oxidationnumber of each atom in each species. Compare your results withyour partner’s. Identify what is being oxidized and reduced, theoxidizing and reducing agents, and describe the transfer ofelectrons. (322-1).

• Construct your own activity series table of strongest to weakestoxidizing agents for metals based on a lab you have designed andcompleted. Compare it with the standard electrode potentialtable and the activity series of metals. (322-1)

Journal

• What does a study of electrochemistry involve? (115-1, 322-1)

• Explain why some reactions are spontaneous and some are not.(322-1)

Paper and Pencil

• Show the species that is oxidized and the species reduced. Identifythe oxidizing agent, reducing agent, oxidation number of eachspecies, and electron transfer in each of the following unbalancedequations:

Fe2+ + MnO4

– + H+ → Fe3+ + Mn2+ + H2O

Cu + NO3– + H+ → Cu2+ + NO + H

2O

(322-1)

• Write half-reactions for each of the following:

Br2 + 2Cl– → Cl

2 + 2Br–

Cu + Cd2+ → Cu2+ + Cd

(322-1)


Investigation 18-A “Single DisplacementReactions”

Chemistry Bulletin “Aging: Is Oxidation aFactor”

Appendix E, p848 “Reduction Half Reactions”


Additional Practice Problems, Chapter 18“Oxidation-Reduction Reactions”

Unit 8 Additional Investigation-A“Obtaining Iron from Iron Oxide”





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Outcomes

ELECTROCHEMISTRY




Redox and Half Reactions5 days (6 hours)

• compare oxidation-reductionreactions with other kinds ofreactions (322-3)– differentiate between oxidation-

reduction reactions and non-redox chemical reactions

– identify half-reactions andchanges in oxidation number

Given a group of equations, students should identify which are redoxreactions and which are not redox. Students should differentiatebetween oxidation-reduction reactions and non-redox reactions byidentifying half-reactions and changes in oxidation number.

Students should assign oxidation numbers to the species undergoingchemical change from examples provided. The lead storage cell inautomobile batteries might be used; the reaction is

Pb + PbO2 + 2H

2SO

4 ⎯ ⎯→←⎯⎯ 2PbSO

4 + 2H

2O

Another example might be a fuel cell used in a spacecraft. It uses thereaction between hydrogen and oxygen gases at a pressure of 50 atmand temperature of 250°C. With graphite electrodes, the followingoverall reaction occurs in the presence of certain catalysts:

2H2 + O2 6 2H2O 0 0 +1 -2

Oxidation Reduction

Students could investigate equations to see which ones involveelectron transfer. From this students could determine if a reaction isan oxidation-reduction reaction (redox). These involve two half-reactions, one oxidation and the other reduction. Teachers might askif anyone found an equation involving transfer of electrons amongmore than two species.

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ELECTROCHEMISTRY


Redox and Half Reactions5 days (6 hours)

Journal

• Explain how to differentiate a redox reaction from a non-redoxreaction. (322-3)

• Is it possible for a double displacement reaction to be a redoxreaction? If so, provide an example. (322-3)

• Is it possible for a single displacement reaction to be a redoxreaction? If so, provide an example. (322-3)

• List some common examples of redox reactions that might occurin your home. (322-3)

Paper and Pencil

• Identify the redox reactions from the following list of reactions.For each redox reaction, identify the species oxidized and thespecies reduced.

1. CaCO3 + H

2SO

4 → CaSO

4 + H

2CO

3

2. Cu + H+ + NO3

– → Cu2+ + NO2 +H

2O

3. CuS + HNO3 → Cu(NO

3)

2 + S + NO + H

2O

4. H2SO

4 + HBr → SO

2 + Br

2 + H

2O

5. NaOH + HCl → NaCl + H2O

MHR Chemistry 726-728



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Outcomes

ELECTROCHEMISTRY




Redox and Half Reactions (continued)

5 days (6 hours)

• write and balance halfreactions and net reactions(322-2 )

– write and balance half reactionsand net reactions using the halfreaction method in neutralsolutions

– balance half and net redoxreactions for complex situationsinvolving acidic and basicsolutions.

Students should write balanced half-reactions, overall reactions, anddetermine if the reaction is spontaneous.

The balanced equation for neutral conditions could be obtained bywriting half-reactions and adding them. One or both equationsmight need to be multiplied by appropriate integers so that thenumber of electrons gained by the oxidizing agent equals thenumber lost by the reducing agent.

For example: (1) Au3+ + 3e- → Au (reduction half )

(2) Zn → Zn2+ + 2e- (oxidation half )

Multiplying equation (1) by 2 and equation (2) by 3 gives thefollowing half reactions: (1) 2Au3+ + 6e- → 2Au

(2) 3Zn → 3Zn2+ + 6e-

Now that the number of electrons gained and lost are equivalent, thehalf reaction equations can be added to give the following netreaction: 2Au3+ + 3Zn → 2Au + 3Zn2+

Many redox reactions occur only in acidic or basic solutions. Acidicsolutions have H+ and H

2O available to take part in the reaction and

must be used to assist in balancing the redox equation. Basicsolutions have OH- and H

2O available to take part in the reaction;

similarly, they must also be used to assist in balancing the redoxequation.

Balancing redox equations under acidic and basic conditions usingthe “half reaction” method requires several steps that must becompleted in a specific order. Students may choose to use the“oxidation number” method, instead of the “half reaction” methodfor balancing redox equations under acidic and basic conditions.

Students could perform a stoichiometric experiment involving aredox reaction. A redox titration would be appropriate and timely asit ties together the stoichiometry from Chemistry 521A and titrationtechniques from the Acids and Bases section of 621A. The balancedredox equation could be given to the students or the students couldbe asked to balance the equation using their newly acquiredknowledge and understanding prior to performing stoichiometriccalculations.

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ELECTROCHEMISTRY


Redox and Half Reactions (continued)

5 days (6 hours)

Paper and Pencil

• Balance the following equations assuming neutral conditions:

Mg + P4 → Mg

3P

2

Sn + PbCl2 → SnCl

2 + Pb (322-2)

• Balance the following equation assuming acidic conditions (usethe oxidation number method and half reaction method):

Fe2+ + MnO4

– → Fe3+ + Mn2+ (322-2)

• Balance the following equation assuming basic conditions (use theoxidation number method and half reaction method):

S2O

32- + NiO

2 → Ni(OH)

2 + SO

32- (322-2)

Performance

• Select the appropriate equipment, and, using it correctly, performan oxidation-reduction titration experiment to determine anunknown concentration of a substance. Include clear organizationof your data, accuracy of results, detailed observations, and correctequations for the reaction. (322-2)


Investigation 18-B “Redox Reactions andBalanced Equations”

Tools & Techniques “The Breathalyzer Test:A Redox Reaction”




BLM 18-1 “The Half-Reaction Method ofBalancing Equations”

BLM 18-2 “The Oxidation NumberMethod for Balancing Equations”





MHR Website



Chem. lab “Redox Titration”



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Outcomes

ELECTROCHEMISTRY




Electrochemical and Electrolytic Cells5 days (6 hours)

• illustrate and label the partsof electrochemical cells andexplain how they work (322-4a)– illustrate, define, and identify

the parts of an electrochemicalcell: anode, cathode, anion,cation, salt bridge/porous cup,and internal and external circuit

– predict and write balancedequations for reactions at thecathode and the anode ofelectrochemical cells

– use galvanic cell notation torepresent a galvanic cell

Outcome 322-4a could be best addressed in a laboratory settingwhere a students could choose one of the electrochemical cellscreated to illustrate and label.

Students should illustrate, define, and identify the parts of anelectrochemical cell: anode, cathode, anion, cation, salt bridge/porous cup, and internal and external circuit. Students shouldidentify the flow of electrons in the external circuit and themigration of ions through the porous barrier or salt bridge.

Consider the following galvanic cell (The Daniel Cell):

Cathode Reaction: Cu2+aq

+ 2 e- ⇔ Cus (Reduction)

Anode Reaction: Zns ⇔ Zn2+

aq + 2e- (Oxidation)

Overall Reaction: Cu2+aq

+ Zns ⇔ Zn2+

aq + Cu

s

Galvanic Cell Notation: Zns | Zn2+

aq || Cu2+

aq | Cu

s

The following outline provides an explanation of galvanic cellnotation using zinc and thallium as the anode and cathode,respectively:

Sn(s) | Sn2+(aq) || Tl+(aq) | Tl (s)

Anode

CathodePhaseBoundary

Porous Barrieror Salt Bridge

Electrolytein oxidationhalf-cell

Electrolytein reductionhalf-cell

Printed with permission from McGraw-Hill Ryerson

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ELECTROCHEMISTRY


Electrochemical and Electrolytic Cells5 days (6 hours)

Journal

• Explain why electrons flow in the external circuit from anode tocathode. (322-4a, 322-7)

Paper and Pencil

• What is an electrochemical cell?(322-4a, 322-7)

• Given a half cell consisting of a zinc electrode immersed in a zincsolution along with a second half cell consisting of a copperelectrode immersed a copper solution, create a labelled drawing ofthe electrochemical cell showing the electron and ion flow.

(322-4a)• Draw a concept map for the following terms: anode, cathode,

anion, cation, salt bridge, internal circuit, external circuit.

(322-4a)

Interview

• Create a list of questions of things you would like to knowregarding the components and operation of electrochemical cells.Use your questions to interview a classmate. (322-4a)

Presentation

• Sketch a cell that forms iron metal from iron II ions whilechanging chromium metal to chromium III ions. Show theelectron and ion flow, label the anode and cathode, and balancethe overall cell equations. (322-4a)

• Role play the behaviour of a particle in an electrochemical cell.(322-4a, 322-7)


Investigation 19-A “ Measuring CellPotentials of Galvanic Cells”



Additional Practice Problems, Chapter 19“Cells and Batteries”

BLM 19.1 “Galvanic Cell Notation”

BLM 19.2 “Electrolytic Cells andGalvanic Cells”

MHR Website

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Outcomes

ELECTROCHEMISTRY




• analyse why and how celltechnology was developedand improved over time(115-5)

• describe and evaluate thedesign of chemical cells andthe way they function,including the technologicaland scientific principles(116-6)

The following two outcomes can be addressed by having studentsconsider many types of primary and secondary batteries, such as: drycell, alkaline, button, lead storage, nicad, and fuel cell.

Students should develop an understanding of why and how celltechnology was developed. Students should describe theconstruction of various cells and the technology used in these cells.Students could identify the science equations involved in a cell.Students could describe how they think chemical cells are made andtheir use. They could look at various cells and evaluate scientificallythe way the cells function. Students might start with thecomponents of a typical flashlight. Students might use a battery,bulb, and two 30 cm lengths of insulated wire to demonstrate whatis needed for a complete circuit. Students might discuss or listproblems that might occur with their circuit.

Students should evaluate experimental designs for cells and identifyor suggest alternatives and improvements. They may provideinteresting ways to configure cells in series to construct a battery toobtain a desired voltage. In small groups, students might look at cellsand compare them. Students might think about the pros and cons ofgasoline versus fuel cell for cars or the reason a battery is used todecompose water. Perhaps the recycling of aluminum, looking at thecorrosion and the economic and social contexts could help studentssee the connections between the technological solutions andscientific principles involved in electrochemistry.

• define problems regardingexperimental designs for cellsand evaluate the processesused in problem solving anddecision making(215-7, 212-2)

Electrochemical and Electrolytic Cells (continued)

5 days (6 hours)

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ELECTROCHEMISTRY


Journal

• For a week/day, keep a record of everything you use that ispowered by batteries. Record the device used and the numberand the type of batteries it contains. (116-6, 115-5)

Paper and Pencil

• List potential uses for various types of batteries and identify thecomponents of the design that make the battery type useful.

(116-6, 115-5)

• An electric eel can produce a charge of 600 V. It does this bycombining the voltages of individual electroplates. If eachelectroplate produces 150 mV, how many plates are required togive off the total discharge? (215-7, 212-2,)

• Write a newspaper article offering ways to reduce the amount ofwaste produced by batteries. (215-7, 212-2)

• Write a short essay about technology that was not and could nothave been available before the development of the nickel-cadmium battery. (116-6, 215-7, 212-2, 115-5)

Presentation

• In small groups, research the environmental effect of differenttypes of batteries. You should analyse both the production costand waste cost. Share your research process and finding with theclass. (215-7, 212-2)

• Research and illustrate the familiar flashlight battery, either theacidic version with the central carbon rod or the alkaline version.

(116-6, 322-4a)


5 days (6 hours)


pp. 787-788

pp. 802-803

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Outcomes

ELECTROCHEMISTRY





5 days (6 hours)

• select and use apparatus andmaterials safely forelectrochemistry labs (213-8)– deduce from their lab activities

that electrochemical cells operateon the energy of spontaneousoxidation-reduction reactions

– define electrolytic cells asrequiring electrical energy tocause non-spontaneousoxidation-reduction reactions tooccur

• construct and test a prototypeof a devise or system andtroubleshoot problems as theyarise (214-14)

• evaluate a personally designedand constructed cell on thebasis of criteria they havedeveloped themselves(214-16)

• design an experimentidentifying and controllingmajor variables (212-3)

• carry out procedurescontrolling the majorvariables and adapting orextending procedures whererequired (213-2)

Students should construct, observe, and describe an electrolytic celland electrochemical cell. They should compare predictions andobservations of electrolytic and electrochemical cells.

Students should deduce from their lab activities that electrochemicalcells operate on the energy of spontaneous oxidation-reductionreactions.

By constructing several electrochemical cells, students could observethe half-cell reaction at each electrode, measure the voltage, and drawa labelled diagram. Students might construct cells using objects suchas lemons, pickles or potatoes. The constructed cells could beconnected in series to create a battery with a cumulative voltage.Other examples to look at include the lead-storage cell, mercury cell,rechargeable cell, or an alkaline cell. Reports on their cells couldinclude a labelled diagram of the cell and an explanation of thepurpose of the salt bridge, direction of electron flow in the externalcircuit, and the equation showing how the cell operates. Othercriteria might be generated through a class discussion.

Students should define electrolytic cells as requiring electrical energyto cause non-spontaneous oxidation-reduction reactions to occur.

Students could construct electrolytic cells and electrolyze someaqueous solutions. Observations of the half-cell reactions includelabelling all parts, predicting and writing equations at the electrodesand the overall redox equations. Calculations of the minimumvoltage to make the electrolytic cell function might be possible.Electroplating an object such as an iron nail (cathode) in a zincsolution with a zinc strip (anode) works well to demonstrate theconcept of electroplating and forcing a non-spontaneous reaction toproceed.

In constructing different cells, students demonstrate their learningand apply their knowledge to explain the function of the cells.

Students should explain, with the aid of a diagram, the operation ofthe electrochemical and electrolytic cells. They should includeexplanations of change in mass and color of the electrodes. Studentsmight look at variables such as size of electrodes and electrolyteconcentration which may influence cell output. They might use oneof the cells they designed as their example.

• formulate operationaldefinitions of major variables(212-7)

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ELECTROCHEMISTRY



5 days (6 hours)

Performance

• Design a cell using simple materials like an orange, a potato, or alemon. (214-16, 212-3, 212-7, 322-4a, 213-2, 214-14)

• Perform an experiment involving the construction and testing ofelectrochemical cells. (213-8, 212-7, 322-4a, 213-2, 214-14)

• Perform an experiment involving the construction of anelectrolytic cell to electroplate a metal. (213-8, 212-7, 322-4b,322-8, 213-2, 214-14)

• Perform an experiment involving the construction of anelectrolytic cell to hydrolyse an aqueous salt solution. (213-8,212-7, 322-4b, 322-8, 213-2, 214-14)

Presentation

• Illustrate and label the parts of an electrochemical cell from yourexperiment. Explain how it works. (322-4a, 214-16)

• Illustrate and label the parts of an electrolytic cell from yourexperiment. Explain how it works. (322-4, 214-16)

Paper and Pencil

• Report on your personally designed device. Include your criteria,procedures, variables, and materials. (214-16, 212-3, 213-8)

• Using experimental data, create a table by placing metals inincreasing order of ease of oxidation (most easily oxidized to leasteasily oxidized)

Portfolio

• Include your laboratory report(s) in your chemistry portfolio.(214-16, 212-7, 322-4, 322-7, 322-8)

MHR Chemistry, pp. x-xiii

Investigation 19-A “Measuring CellPotentials of Galvanic Cells”

Investigation 19-B “Electrolysis of AqueousPotassium Iodide”

Investigation 19-C “Electroplating”








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Outcomes

ELECTROCHEMISTRY




Redox Reactions with Standard Reduction Potentials3 days (3.5 hours)

• predict the voltage of variouselectrochemical cells (322-6)– use either of the following

formulae to calculate cellpotential:E0

cell=E0

cathode - E0

anode

ORE0

cell=E0

red + E0

oxid

Students should predict the voltage of electrochemical cells based onrelative location of the metals involved from a table of standardreduction potentials or table containing an activity series of metals.

Some examples might be

Fe + MnO4– + H+ → Fe2+ + Mn2+ + H

2O

or

Ag+ + Fe2+ → Fe3+ + Ag

or

Zn + Cu2+ → Zn2+ + Cu

Students could assign oxidation numbers to species undergoingchemical change, and they could combine their knowledge of celldiagrams with equations. Cell potentials are not altered by thefactors used to balance the electrons. Students might look atexamples of redox reactions used in industry and write the equationsand calculate the potential of these reactions. Food processing, watertreatment, corrosion, metallurgy, or respiration might be used forexamples.

Student should be familiar with the standard conditions forreduction potential as being 250 C, 1 atm, 1 mol/L.

Students should compare lab and theoretical data and account forpossible differences in reduction potentials or cell potentials.Students might discuss how reduction potentials can be measured.The unit of electrical potential is the volt, V, which can be measuredwith an analog or digital voltmeter. Students should develop anunderstanding of how discrepancies occur between theoretical andexperimental values of voltage such as solution concentration,instrument calibration, temperature, etc.. By making and testingseveral types of cells, data for evaluation will be available. Studentscould perform an experiment to test predictions about thespontaneity of oxidation-reduction reactions based on calculated cellpotentials or the positioning of half cell equations on a table ofstandard reduction potentials.

• evaluate the reliability of dataand data collection methodsinvolving reduction potentials(214-8)

• compare theoretical andexperimental reductionpotential values and accountfor discrepancies (214-7)

Students should evaluate reduction potential data and the methodsand conditions used to collect them. Students could obtaintheoretical data from both print and electronic sources. They shouldconfirm the reliability of the theoretical data by ensuring it isassociated with a professional association such as Merck, CRC, orIUPAC. Experimentally, students could vary the instruments andconditions used to collect data which would provide them withevidence of the reliability of the data and allow them to betteraccount for discrepancies between experimental and theoreticalvalues.

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ELECTROCHEMISTRY


Redox Reactions with Standard Reduction Potentials3 days (3.5 hours)

Performance

• Design and test a basic cell of your choice. Compare your resultswith a table of standard reduction potentials. Comment. (214-8,214-7)

Paper and Pencil

• Calculate the E0cell

value for electrochemical cells which you createduring an experiment. (322-6)

• Compare experimental voltages with theoretical E0cell

values andaccount for discrepancies. (214-7)

• Discuss various methods used to find reduction potential.Compare theoretical and experimental reduction potential values.(214-7, 214-8)





ThoughtLab “Assigning Reference Values”

MHR Website

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Outcomes

ELECTROCHEMISTRY




Redox Reactions with Standard Reduction Potentials (continued)

3 days (3.5 hours)

• predict whether oxidation-reduction reactions arespontaneous based on theirreduction potentials (322-5)– define a spontaneous reaction as

one that produces a positive cellpotential

– write and balance oxidation-reduction reactions using half-reaction equations obtainedfrom a standard reductionpotential table

Students should define a spontaneous reaction as one that produces apositive cell potential. Using the table of standard reductionpotentials students should predict the spontaneity of redox reactionson the basis of calculated standard cell potential values, and therelative positions of half-reduction equations on a standard reductionpotential table.

Students could write and balance oxidation-reduction reactions usinghalf-reaction equations obtained from a standard reduction potentialtable. Students should understand that the scientific community hasuniversally accepted the values for half-reaction potentials based onthe 2H+ + 2e– → H

2 half cell (E0

cell= 0 V) under standard conditions

of ideal behaviour. Two manipulations are often required to obtain abalanced redox reaction. One of the reduction half-reactions must bereversed, which means that the sign of the potential for this half-reaction must also be reversed. Since the number of electrons lostmust equal the number gained, half-reactions must be multiplied byintegers for electron balance. Students should know the value E° isnot changed when a half cell is multiplied by a factor; the standardreduction potential, E° , does not depend on how many times thereaction occurs. From their cell diagrams that showed electronsflowing from the anode to the cathode, students might describe thecell process.

Students could consider the cell

Cu(s) + Fe3+(aq) → Cu2+(aq) + Fe2+(aq)

Students could develop simple half-reaction equations frominformation provided about redox changes. So, the following uses theabove example:

• Cu2+ + 2e– → Cu E° = 0.34V

• Fe3+ + e– → Fe2+ E° = 0.77V

To balance and calculate the standard cell potential, the copper reaction,(1) must be reversed Cu → Cu2+ + 2e– E° = –0.34V. Then, to balancethe electrons, (2) must be multiplied by 2:

2Fe3+ + 2e– → 2Fe2+ E° = 0.77V

Now, by adding the two reactions, the balanced cell reaction couldbe found:

Cu → Cu2+ + 2e– E° = –0.34V (E0oxid

)

2Fe3+ + 2e– → 2Fe2+ E° = 0.77V (E0red

)

Cu(s) + 2Fe3+(aq) → Cu2+(aq) + 2Fe2+(aq) E°cell

= –0.34V + 0.77V

95


ELECTROCHEMISTRY


Redox Reactions with Standard Reduction Potentials (continued)

3 days (3.5 hours)

Paper and Pencil

• Predict whether the following reactions are possible:– oxidation of iron atoms by silver ions– oxidation of bromide ion by chlorine– reduction of iodine by fluoride ion(322-5, 322-6)

• Write the balanced equation for the reaction of copper with dilutenitric acid. Is this reaction spontaneous? Support your answers.(322-5, 322-6)

• Will the reaction of cadmium metal and copper II ions bespontaneous? Support your answer. (322-5, 322-6)

Presentation

• Diagram a cell in which the reaction consists of the displacementof silver from AgNO

3 by metallic copper to produce Ag(s). Write

the equation for the half-reaction that takes place in each half-cell,identifying each as oxidation or reduction. Then write theequation for the total cell reaction. (322-5)

• Construct an activity series table of strongest to weakest oxidizingagents for metals based on an experiment you have completed.Compare your activity series table with a standard electricpotential table. (322-5, 214-7, 214-8)

Journal

• Explain why some reactions are spontaneous, while others are not.(322-5)

• Explain how you would determine, from a table of standardreduction potentials, how to place various metals such as Au, Ag,Fe, Cu, Zn in order from strongest to weakest oxidizing agent (orin increasing order of oxidation potential). (322-5)





MHR Website

96

Outcomes

ELECTROCHEMISTRY





5 days (6 hours)

• illustrate and label the partsof an electrolytic cell andexplain how they work(322-4b)– define and identify, on a

diagram of an electrolytic cell,the following: anode, cathode,anion, cation, power supply andinternal and external circuit

– predict and write balancedequations for reactions at thecathode and the anode of theelectrolytic cells

Outcome 322-4b could be best addressed in a laboratory settingwhere students can choose one of the electrolytic cells created toillustrate and label.

Students should illustrate and label the parts of electrolytic cell andexplain how they work. Students should define and identify, on adiagram of an electrolytic cell, the following: anode, cathode, anion,cation, and power supply. Students should recognize thatelectrolytic cells require an external energy source to force a non-spontaneous reaction to proceed. Students should identify the flowof electrons and the migration of ions for an electrolytic cell.

• explain the processes ofelectrolysis and electroplating(322-8)

– predict the voltage required forthe electrolysis of a molten salt

– predict the voltage required andthe products of the electrolysisof an aqueous solution

Students should explain the process of electrolysis. The practicalimportance of electrolysis could be discussed by using examples such ascharging a battery, chrome plating an object, or producing aluminummetals. Electroplating industries are common. Students shouldpredict the voltage required and the products of the electrolysis of anaqueous solution as the hydrolysis of water and the salt are bothpossible when an electric current is passed through an aqueous saltsolution. Students should predict the voltage required for theelectrolysis of a molten salt.

Students should explain the process of electroplating. Students coulduse the example of silver on flatware or jewellery. A sample could beset up by depositing copper metal from copper (II) sulfate solution,on a strip, such as zinc. Similarly, the depositing of zinc on an ironstrip or nail from a zinc solution could be demonstrated along with adiscussion related to galvanizing and cathodic prevention.

Cathode Reaction: Zn2+aq

+ 2e- ⇔ Zns (Reduction)

Anode Reaction: Cus ⇔ Cu2+

aq + 2 e- (Oxidation)

Overall Reaction: Zn2+aq

+ Cus ⇔ Cu2+

aq + Zn

s


97


ELECTROCHEMISTRY



5 days (6 hours)

Paper and Pencil

• A sunken ship is to be lifted from the ocean bottom. Plastic bags,containing seaweed and equipped with an arrangement of inertand internal and external electrodes, are attached to the ship.Electrical current is applied to the electrodes, to fill the bags withhydrogen gas. Is the internal electrode the anode or cathode?Explain. What are the products at the other electrode? (322-8)

• Should you use zinc or copper or either to “plate out” nickelmetal from a nickel (II) nitrate solution? Explain. (322-8)

• Given an external battery and a half cell consisting of a zincelectrode immersed in a zinc solution along with a second half cellconsisting of a copper electrode immersed in a copper solution,create a labelled drawing of the electrolytic cell showing theelectron and ion flow. (322-4b)

• Predict the products of the hydrolysis of a 1 M solution of NaCl.(322-8)

• Write the chemical equations for the reactions that occur at theanode and cathode during the electrolysis of molten calciumchloride. (322-8)

Interview

• Create a list of questions of things you would like to knowregarding the components and operation of electrolytic cells. Useyour questions to interview a classmate. (322-4b)

Journal

• Explain why the negative terminal of the external voltage source isconnected to the cathode in an electrolytic cell. (322-4b)

Presentation

• Sketch an electrolytic cell that forms iron II ions from iron metalwhile changing chromium III ions to chromium metal resultingfrom an external voltage. Show the electron and ion flow, label theanode and cathode, and balance the overall cell equation.

(322-4b)


pp. 794-796




MHR Website

98

Outcomes

ELECTROCHEMISTRY




Energy Efficiency of Cells2 days (2.5 hours)

• evaluate the design of atechnology and the way itfunctions on the basis of avariety of criteria that theyhave identified themselves(118-4)

Students should establish criteria to evaluate different technologicaldesigns used in electroplating and electrolysis. Students could evaluatehow the technology design functions as a reliable source. Students couldexplain how cells both natural and technological play a role in everydaylife. Students could evaluate the potential applications of various cellsbased on criteria they have determined. Industrial extraction ofmetal, water treatment, or corrosion prevention could be addressed.

• explain how electrical energyis produced in a hydrogenfuel cell (322-9)

• analyse natural andtechnological systems tointerpret and explain theirstructure and dynamics(116-7)

• identify and evaluatepotential applications offindings (214-18)

Students should eexplain how electrical energy is produced in ahydrogen fuel cell and identify and evaluate potential applications ofthis energy source.

Students could talk about the industrial uses and the industrialpreparation of hydrogen. Hydrogen’s use in unsaturated vegetable oilsand its use to cool superconducting materials could be explored.Students could investigate the liquid hydrogen that is used to fuelrockets that launch satellites and power spacecrafts. Encouragestudents to suggest questions, such as “What drives the H

2

combustion reaction?” and “Would the use of hydrogen-powered carslead to less pollution?” Such questions could lead to an explanationof how electrical energy is produced in a hydrogen fuel cell.

• compare electrochemical andelectrolytic cells in terms ofenergy efficiency, electronflow/transfer, and chemicalchange (322-7)– predict and write balanced

equations for reactions at thecathode and the anode ofelectrochemical and electrolyticcells

Students should predict and write balanced equations for reactions atthe cathode and the anode of electrochemical and electrolytic cells.Students should recognize that electrolytic cells require an externalenergy source to force a non-spontaneous reaction to proceed,whereas electrochemical cells operate spontaneously.


99


ELECTROCHEMISTRY


Energy Efficiency of Cells2 days (2.5 hours)

Paper and Pencil

• Describe how electrical energy is produced in a hydrogen fuelcell. (322-9)

• What are the benefits and drawbacks associated with hydrogen fuelcells? (322-9)

• What is an electrochemical cell? an electrolytic cell?

(322-4, 322-7)• Create a table illustrating the similarities and differences between

electrochemical and electrolytic cells. (322-4, 322-7)

Journal

• In a half-cell, what is being conserved? (322-7)

• All halogens kill bacteria and other microorganisms. Chlorine is ahalogen that is safe enough and readily available for large-scaletreatment of public water supplies. What happens to thehypochlorous acid formed when Cl

2(g) is added to H

2O(l)?

(118-4)

Presentation

• Illustrate and label the components of a electrochemical/electrolytic cell. Present how the cells function to the class.(322-4, 322-7)

• Explain how an electrochemical cell can be converted to anelectrolytic cell. (322-7)

MHR Chemistry, pp. 780, 796,

pp. 798-805




Additional Investigation Unit 8 B

“Rusting and Corrosion Prevention”

MHR Website

Appendix A

Thermochemistry (25 days, 30 hours)

From Solutions to Kinetics to Equilibrium (13 days, 16 hours)

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Electrochemistry (17.5 days, 21 hours)


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Chemistry - Prince Edward Island · Curriculum (1998). Chemistry 521A includes the following...

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Transcript of Chemistry - Prince Edward Island · Curriculum (1998). Chemistry 521A includes the following...