CHAPTER 1

Introduction to Chemistry

Vocabulary/Study Guide

• Define each term using the Glossary• Either write on the handout, or use your own

paper• This is due on Test Day (tentatively, Tuesday,

August 27)

Section 1: A Story of Two Substances

• National Standards:– UCP.1 Systems, order, and organization– UCP.2 Evidence, models, and explanation– A.1 Abilities necessary to do scientific inquiry– A.2 Understandings about scientific inquiry– B.3 Chemical reactions– B.6 Interactions of energy and matter– E.2 Understandings about science and technology– F.4 Environmental quality– F.5 Natural and human-induced hazards– G.2 Nature of scientific knowledge– G.3 Historical perspectives

Essential Questions

• What is a substance?• How does ozone form and why is it important?• What are chlorofluorocarbons and how do

they get into the atmosphere?

Why Study Chemistry?

• All the stuff in the universe is made from building blocks formed in stars– These building blocks are called matter – anything

that has mass and takes up space• Chemistry is the study of matter and the

changes that it undergoes

The Ozone Layer

• Overexposure to ultraviolet radiation is harmful to both plants and animals

• Increased levels of UVB can cause cataracts, skin cancer, lower crop yields in agriculture, and disrupted food chains in nature

• Ozone (O₃) is a substance in the atmosphere that absorbs most harmful UV radiation before it reaches Earth’s surface– substance: matter that has a definite composition; also

known as a chemical

• The ozone layer that protects Earth is located in the stratosphere, that layer of Earth’s atmosphere just above the troposphere (where we live)

Ozone forms over the equator, where the rays of sunlight are the strongest, and then flows toward the poles.

Between 1981 and 1983, a research group from the British Antarctic Survey measured surprising low l levels of ozone, especially during the Antarctic spring in October.

Chlorofluorocarbons

• In the 1920’s, large-scale production of refrigerators began, which used ammonia as coolant.

• In an attempt to find safer coolant, chemist, Thomas Midgley, Jr. synthesized the first chlorofluorocarbons in 1928.

CFC’s (con’t)• A Chlorofluorocarbon (CFC) is a substance that

consists of chlorine, fluorine and carbon. • All substances that are classified as CFCs are:

– Man-made (they do not occur naturally)– Nontoxic– Stable (they do not readily react with other substances)• Because of being nontoxic and very stable, they

seemed to be ideal coolants for refrigerators and AC units, for use in plastic foams and as propellants in spray cans.

• CFCs were first detected in the atmosphere in the 1970s, and the concentrations continued to increase through the 1990s.

• Could there be a connection between ozone thinning and increasing CFCs in the atmosphere?

Homework

• SECTION 1 REVIEW, Page 8• Questions #1, 3, 4, 5, 6, 7• Answer with complete sentences• Due tomorrow

Section 2: Chemistry and Matter

• National Standards:– UCP.1 Systems, order, and organization– UCP.2 Evidence, models, and explanation– A.1 Abilities necessary to do scientific inquiry– B.2 Structure and properties of matter– G.1 Science as a human endeavor– G.2 Nature of scientific knowledge

Essential Questions

• How do mass and weight compare and contrast?

• Why are chemists interested in a submicroscopic description of matter?

• What defines the various branches of chemistry?

Matter and its Characteristics

• Matter is anything that has mass and takes up space

• Mass is a measure that reflects the amount of matter

• Is air matter? {DEMOS}– Matter has mass (balloon, scale)– Matter takes up space (beaker with water,

paper cup, tissue, scissors)

Matter and its Characteristics

• Weight is a measure of the effect of Earth’s gravitational pull on matter– This varies from place to place on Earth, and from

planet to planet

• Scientists use mass for measurements so they can compare the measurements that they make in different parts of the world

MASS vs. WEIGHT

MASS• Measures the amount of

matter• Is constant• The units are grams and

kilograms

WEIGHT• Measures the pull/force of

gravity• Varies from place to place• The units are ounces and

pounds

Matter and its Characteristics

• Much of matter and its behavior is macroscopic• Matter can be broken down into more than a

hundred types of matter called elements– Elements are made up of particles called atoms

• The structure, composition, and behavior of all matter can be explained on a submicroscopic level– Also called the atomic level

• All that we observe about matter depends on atoms and the changes they undergo

Matter and its Characteristics

• Chemistry explains events on the atomic level (submicroscopic) that cause macroscopic observations.

• A model is a verbal, visual, or mathematical explanation of experimental data.

Chemistry: The Central ScienceChemistry is traditionally broken into branches that focus on specific areas such

as:

Homework

• SECTION 2 REVIEW, Page 11• Questions #8, 9, 12, 13• Answer with complete sentences• Due tomorrow

Section 3: Scientific Methods

• National Standards:– UCP.1 Systems, order, and organization– UCP.2 Evidence, models, and explanation– A.2 Understandings about scientific inquiry– G.1 Science as a human endeavor– G.2 Nature of scientific knowledge

Essential Questions

• What are the common steps of scientific methods?

• What are the similarities and differences between qualitative data and quantitative data?

• In an experiment, which variable is the independent variable, which is the dependent variable, and which are controls?

• What is the difference between a theory and a scientific law?

A Systematic Approach

• It is helpful if all scientists use common procedures as they conduct their experiments

• A scientific method is a systematic approach used in scientific study– This is an organized process used by scientists to do

research, and – It provides a method for scientists to verify the work of

others• If other scientists cannot confirm the results after

repeating the methods, then doubt arises over the validity of the results

A Systematic Approach (cont.)

The steps in a scientific method are repeated until a hypothesis is supported or discarded.

SECTION1.3

Scientific Methods

A Systematic Approach

Qualitative Data• Uses the five senses – how

something looks, feels, sounds, tastes, or smells

• Information that describes color, odor, shape, or some other physical characteristic

• People’s responses on surveys would be a type of qualitative data

Quantitative Data• Numerical information such

as temperature, pressure, volume, the quantity of a chemical formed, or how much of a chemical is used up in a reaction

• Tells how much, how little, how big, how tall, or how fast

• People’s scores on tests would be quantitative data

A Systematic Approach

• An experiment is a set of controlled observations that test the hypothesis

• A variable is a quantity or condition that can have more than one value– An independent variable is the variable you plan to

change.– The dependent variable is the variable that changes in

value in response to a change in the independent variable.

– A control is a standard for comparison

A Systematic Approach

• Writing a Lab Report includes:– Title– Objective or Hypotheses– Prediction– Data– Analysis– Conclusion

Mini-Lab: Develop Observation Skills

TITLE: DEVELOP OBSERVATION SKILLS OBJECTIVE: Students need to understand the importance of

observation skills in Chemistry because observations are often used to make inferences.

PREDICTION:Define inference.

How will dishwashing detergent affect vegetable oil?

How will dishwashing detergent affect whole milk?

Molina and Rowland’s model showed how CFCs could destroy ozone.

A Systematic Approach (cont.)

SECTION1.3

Scientific Methods

Theory and Scientific Law

Theory• An explanation of a natural

phenomenon based on many observations and investigations over time

• States a broad principle of nature that has been supported over time

• Still subject to new experimental data and can be modified

• A theory is considered valid if it can be used to make predictions that are proven true

Scientific Law• A relationship in nature that is

supported by many experiments• Many scientists come to the

same conclusion about certain relationships in nature and they find no exceptions to these relationships

• Scientists develop further hypotheses and experiments to explain why these relationships exist

Homework

• SECTION 3 REVIEW, Page 16• Questions #17, 18, 19• Answer with complete sentences• Due tomorrow

Section 4: Scientific Research• National Standards:

– UCP.1 Systems, order, and organization– UCP.2 Evidence, models, and explanation– A.1 Abilities necessary to do scientific inquiry– A.2 Understandings about scientific inquiry– B.2 Structure and properties of matter– B.6 Interactions of energy and matter– E.2 Understandings about science and technology– F.1 Personal and community health– F.4 Environmental quality– F.6 Science and technology in local, national, and global challenges– G.1 Science as a human endeavor– G.2 Nature of scientific knowledge– G.3 Historical perspectives

Essential Questions

• How do pure research, applied research, and technology compare and contrast?

• What are some of the important rules for laboratory safety?

Types of Scientific Investigations

• Pure research is research to gain knowledge for the sake of knowledge itself.

• Applied research is research undertaken to solve a specific problem.

• Chance discoveries occur when scientists obtain results that are far different from what they expected.– Ex. Alexander Fleming’s discovery of Penicillin.

Students in the Laboratory

• You are responsible for your safety and the safety of others around you.

• Refer to Table 1.2 on page 19 of your textbook for a list of safety rules in the laboratory.

The Story Continues

• Applied research showed that CFCs and a few other chemicals react with ozone.

• Many nations agreed in 1987 to the Montreal Protocol, to phase out CFC use.

Data Analysis Lab: Interpret Graphs

Title: Interpret Graphs (page 21)Objective: To determine how ozone levels vary throughout the year.Think Critically:

– 1. Describe the trend in the data for 1979-2008.– 2. Evaluate how the 2009 data compare with the data from

1979-2008.– 3. Identify the month during which the ozone levels were

the lowest in 1979-2008. In 2009?– 4. Assess – Do these data points back up what you learned

in this chapter about ozone depletion? Explain your answer.

The Benefits of Chemistry

• Chemists solve many real problems we face today such as:– Ozone depletion– Finding cures for diseases– Reducing automobile pollution

Homework

• SECTION 4 REVIEW, Page 22• Questions #20, 23, 24• Answer with complete sentences• Due tomorrow