CHM 212 Quantitative Analysis

Fall 2010

Professor Dr. Jason R. Dwyer

318 Pastore jdwyer@chm.uri.edu (Please put CHM212 in the subject line) Office hours: By drop-in (if I am available), or by appointment

Teaching Assistant Brian Kite, bkite@chm.uri.edu.

Lectures Tuesdays and Thursdays, 11:00-12:15, Pastore 234

Laboratories Mandatory safety training takes place during the FIRST week of labs.

Course Material

Textbook Harris, Quantitative Chemical Analysis, 8th ed. WH Freeman. Either

(1) Hardcover ISBN 1429218150 (2) Loose-leaf ISBN 1429263091 (in the bookstore)

Solution Manual (recommended) ISBN 1429231238

Bundled textbook and solution manual ISBN 1429266317

Lab Manual See the course webpage and print the instructions off prior to arriving in the lab: they will not be available in the lab.

Lab Notebook Must have duplicating (eg. carbon or carbonless) sheets and numbered pages (may be numbered by hand). Available at campus bookstore. Spiral-bound notebooks, or other books in which it is difficult to detect if a page has been ripped out, are not acceptable. You must have the lab notebook to carry out

an experiment—without a lab notebook you will not be permitted to carry out the experiment. All records must be made in your lab notebook—nothing on loose sheets of paper.

Reference Material To find physical and chemical constants such as the pKa of an acid, you should be using (and properly referencing):

1. Your textbook [you may reference as “text”] 2. CRC Handbook of Chemistry and Physics 3. Lange’s Handbook of Chemistry 4. Merck Index 5. Primary peer-reviewed (journal) articles 6. Company websites for proprietary information only, or when no alternative exists, or for MSDS

information Use of non-academic references such as Wikipedia or non-peer-reviewed websites (even if university websites!) will result in a mark of 0 for that question. You need not reference a “known” reference value such as a molecular weight—ask me if you have any questions.

Lab Personal Protective Equipment 1. Chemistry Stockroom: Pastore 210. RAM account sales only. 2. Safety goggles or safety glasses. Available in Pastore 215 Sept. 8-17, 10am-2pm cash-only, or

thereafter in the chemistry stockroom, RAM account only. 3. Knee-and wrist-length lab coat, available from the stockroom. Your clothing must provide

additional protection below your knees: short and open-toed or open-heeled shoes are unacceptable attire in the laboratory. Socks are also required.

4. Chemical-resistant nitrile gloves from the stockroom. Latex gloves are forbidden. 5. If you forget your personal protective equipment, you will have to purchase a replacement set.

Lecture Requirements There will be unannounced quizzes given during lecture periods, so be prepared with:

1. Scientific calculator 2. Pen: any work submitted for remarking must be in pen or be a computer printout.

Regular attendance is important: quizzes will be given without prior announcement. For tests and exams, computers, internet-capable devices and cell phones are prohibited. Any device enabling wireless communication during a test or exam is prohibited.

Requirements for Submitted Work 1. Laboratory reports must be written entirely in pen or be word-processed. 2. Any work submitted for remarking must have been originally in pen or have been a computer

printout. 3. All answers must be clearly explained—no marks will be given for an insufficiently explained

answer. 4. Submitted work must be legible and neatly and clearly organized. Messy or difficult-to-

understand answers will be given a mark of 0.

Course Grading1 Laboratory Experiments

2,3,4 35%

Homework5 and Quizzes 20%

In-class Exams (2) 20%

Final Examination 25%

1 Plagiarized work will be given a mark of 0—a single instance of plagiarism in any submitted work will

result in a mark of 0 for the entire work—and disciplinary action will be pursued. See section on Academic Honesty. 2 Failure to work safely constitutes failure as an experimental scientist. Willful negligence will result in

immediate expulsion from the laboratory for the duration of the course and a mark of 0% for the course. 3 Excluding willful negligence, the first violation of a safety regulation may result in immediate expulsion

from the laboratory and a mark of 0 for that laboratory. The second violation may result in expulsion from the laboratory for the duration of the course and a mark of 0% for the course. 4 To pass the course, the student must complete at least 6 of the 7 experiments and the comprehensive

lab exam. A missed experiment will be given a mark of 0. 5 Submitted homework and assignments must be legible and neatly and clearly organized. Messy or

difficult-to-understand answers will be given a mark of 0. Similarly, answers must be fully explained—no marks will be given for a final answer without sufficient supporting background explanation.

Laboratory Experiment Grading Distribution of the 35% lab mark: Quizzes 10% Performance 20% Reports and results 50% Formal lab report 10% Final Lab exam 10%

Safety Failure to work safely constitutes failure as an experimental scientist. Willful negligence will result in immediate expulsion from the laboratory for the duration of the course and a mark of 0% for the course. Otherwise, the first violation of a safety regulation may result in immediate expulsion from the laboratory and a mark of 0 for that laboratory. The second violation may then result in expulsion from the laboratory for the duration of the course and a mark of 0% for the course. Safety violations include, but are not limited to:

1. Improper disposal of chemical waste 2. Failure to wear the proper personal protective items. 3. Touching door handles, telephones, your face, etc., with a gloved hand.

Laboratory Preparation Students are required to prepare for each experiment by having read and understood the experiment instructions and having prepared an experimental plan that includes the experiment title, purpose, a brief introduction, preliminary calculations and data tables to accept results from the experiment. While the procedure must be in words, it is recommended that you additionally include a flow-chart or diagram showing the experimental stages so that you can more efficiently plan your time. You must also prepare a section listing the chemicals you will be using, and summarizing safety information,

including proper disposal methods, to show that you have read over the Material Safety Data Sheet (MSDS) for that chemical. Be prudent always, and especially mindful of compounds that are teratogens, mutagens, explosion hazards. To find MSDS, go to: http://www.uri.edu/safety/chem.html, http://www.msdssearch.com/DBLinksN.htm. For an aqueous 50% NaOH solution, for example, an MSDS can be found through the latter site at https://fscimage.fishersci.com/msds/95586.htm. If you have not prepared for your lab experiment, you will not be permitted to start the lab.

Laboratory Quizzes Quizzes given before the start of the lab are to test your preparation and your understanding of the experiment you are about to perform. To do well, you should prepare your experimental plan and think about what you are doing in each step and why. This though process will improve your lab performance and results.

Laboratory Performance During each experiment, the lab instructor will assess each student’s performance in the lab for appropriate laboratory behaviour and technique. Marks will be awarded for demonstrating familiarity with the experimental procedure, demonstrating proper experimental technique, properly using the lab notebook to record data and observations, keeping personal lab bench and communal areas clean, efficiently and politely sharing common equipment, properly disposing of chemical waste, adhering to safety regulations and interacting appropriately with fellow students and the teaching assistant. You should also work hard to ensure that you work efficiently and use your allotted time wisely. Marks will be deducted for improper experimental technique, leaving personal lab bench or communal work areas messy, and related behaviors. Note: Failure to be ready to leave the laboratory at the end of the experiment will result in deducted marks—and you must nevertheless leave the laboratory. You must have stored all of your materials and tidied common and personal workspaces before being considered ready to leave.

Laboratory Reports The laboratory report sheet is due at the beginning of the next meeting of the lab section. The relevant carbon copy pages from the lab notebook must be handed in during each lab period: pre-lab work at the beginning, and results and observations at the end. Late lab reports will be deducted 20% for each day that they are late.

Laboratory Requirements 1. Scientific calculator. 2. All lab book records must be written in permanent ink—no water-based inks are permitted. 3. At the beginning of each lab period, you must have a completed experimental plan (this includes

MSDS information) in your lab notebook. Without such a plan you will not be permitted to perform the experiment and will receive a mark of 0 for that lab report.

Group Work Students are encouraged to work in groups, however all submitted work must then:

1. include the names of all group members

2. credit any key steps in a solution to the person who proposed them (if the effort was not collective)

3. be in your words alone: superficial similarity between assignments may be difficult to avoid in this circumstance, but the details of your submitted work should be unique to you.

Absence Due to Illness Any due dates or testing dates missed because of illness must be supported by valid medical

documentation. There is no guarantee that a missed lab can be made up, but it is the student’s

responsibility to make timely arrangements to make up a missed lab experiment and to get

permission in advance for doing so.

Academic Honesty Academic dishonesty in any form is considered a serious offence, and disciplinary action will be taken immediately. The URI policy on academic honesty is detailed in the student handbook (available online), and it is summarized below: Students are expected to be honest in all academic work. A student’s name on any written work, including assignments, lab reports, papers, or exams, shall be regarded as assurance that the work is the result of the student’s own thought and study. Work should be stated in the student’s own words, and produced without assistance (or properly attributed to its source). When students are authorized to work jointly, group effort must be indicated on the work submitted. The following are examples of academic dishonesty:

Unauthorized communication during exams.

Unauthorized use of another’s work or preparing work for another student.

Taking an exam for another student.

Altering or attempting to alter grades.

The use of notes or electronic devices such as calculators, computers, or cell phones to gain an unauthorized advantage during exams.

Fabricating or falsifying facts, data, or references.

Facilitating or aiding another’s academic dishonesty. When there is an allegation of academic dishonesty, the instructor may:

Fail the student for the assignment, or recommend that the student fail the course. Students in CHM 212 are permitted to work in groups on assignments and lab reports, but the names of all participating students should appear on each submitted assignment and report. If one student in particular is responsible for a key concept in the solution or write-up, then s/he should be given explicit credit right next to that line of the report. Note that all submitted work must still be completed by each student in his or her own words: shared text is not permitted. Simply making small text substitutions (eg. “But” instead of “However”) or rearranging sentences, for example, are not consistent with the expectation that each student is reporting his or her work in his or her own words.

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CHM 212

Laboratory Notebook Use and Lab Report Requirements and Guidelines

Keeping a laboratory notebook

The laboratory notebook is considered a legal record that can be used to support patent

claims and protect against lawsuits. It is a careful and detailed record of the experiments

that you performed, the results that you observed and the conclusions that you drew.

Knowing how to keep a proper lab book is a vital skill in industry and academia. The

degree to which you follow these requirements will affect your lab performance grade.

1. Your name or student number must be on the cover of the lab notebook and at

least the first carbon sheet that you will hand in. You should also include your lab

section number.

2. All pages must be numbered.

3. The first 4 pages of your notebook are reserved for a Table of Contents, listing

date, lab number, title and page. Do *not* leave these pages blank: make them

each into a table of contents now, and fill in the fields as you complete your labs.

4. Your next page should be left for a diagram of the lab in which the locations of

fire extinguisher(s), eyewash station(s), safety shower(s), and exit(s) are marked.

You should additionally sketch the emergency escape route.

5. Once you have started writing in your notebook, there should be no blank pages

(blank left pages in book-style notebooks are acceptable, since they are only for

rough work). Nor should there be blank spaces between text. To enable you to

hand in carbon sheets for before- and during-lab work, start your

observations/data section on a fresh page and draw a line from the pre-lab

questions section to the bottom of its page so that you can no longer write on that

page.

6. For CHM212, you are required to have a lab book with duplicate pages that will

be handed in during every lab period. When you enter the lab, you must hand in

the carbons for the material you must have already prepared. Experimental

carbons are to be handed in at the end.

7. Use permanent ink, only: no pencil, no water-soluble ink.

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8. Your writing must be legible.

9. Spelling counts: sodium sulfate and sodium sulfite are different chemicals!

10. Never remove pages from a lab book.

11. If you make an error, draw a single line through the error so that the original

writing can be seen. Never scratch out an error. Initial and date next to your

correction.

12. Write original data into your lab book. Do *not* write values on a paper towel

“for now”, to copy them over later. Your TAs will dispose of any scrap of paper,

etc., on which data has been temporarily recorded.

13. Any paper that you wish to include in your lab book should be folded or cut to

size and permanently secured to the page. Glue is best, staples and tape are less

favorable options. You must then sign and date across the interface of the

notebook page and what you have attached: half of the date and your signature is

on the notebook page, the other half is on the attached page.

14. If you have a bound book-form notebook, the left side is reserved for rough work

and calculations, and the right side is reserved for the permanent record of your

work. Data is entered ONLY on the right side; never on the left and then later

copied to the right side.

15. Please read through the document found at http://www.mh-

hannover.de/fileadmin/mhh/download/international/hbrs_mdphd/HBRS/How_to_

keep_a_lab_notebook.pdf, and note that these general rules for keeping a lab

notebook are global.

Laboratory Preparation

To prepare for your lab, you should thoroughly read through the provided laboratory

procedure, treating it as a guide to carry out a scientific experiment that requires your

active thought throughout, and not a set of steps that you are merely required to follow

without thinking. Since you will be graded on your in-lab performance, it is important to

think through how you would actually perform the experiment, plan your time wisely, be

alert to possible pitfalls, and do as much preliminary work as is possible before ever

setting foot in the lab.

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For each new lab, you must begin your experimental plan with the following. Use

headings (larger text, underlined, etc.) to divide your report into logical sections.

Your name or student number, the date, your TA’s name and your laboratory

section.

The lab number and title

Title/purpose of experiment. Concisely explain the purpose of the experiment.

Materials and methods. List chemicals along with relevant chemical information

such as molecular weights and densities. List any special equipment here, such as

a pH meter.

Safety information: Summarize important safety information such as chemical

hazards and safe disposal procedures listed in MSDS sheets—see Course Syllabus

for instructions. Note that local safety procedures (see

http://www.chm.uri.edu/show_content.php?topic=jentest&email=stockroom&fro

m=forcurrstuds) take precedence over MSDS sheet procedures when there is

inconsistent information. Check with your TA. This uncertainty should indicate

to you that there are unknowns in dealing with chemicals, and safe procedures

should be used in every instance of interacting with them.

Pre-lab Questions

Experimental Procedure: List what you are going to do during the lab section.

This must be in words, but adding flow chart of process steps can help to identify

possible bottlenecks. Include any preliminary calculations that you needed for

planning the lab, and show all steps of those calculations. Your procedure should

enable any other experimenter to understand what you did, and to repeat it if

necessary. It should be only as long as necessary to accomplish this goal.

Experimental Results: Have a table (with title) prepared—before you enter the

lab—where you will enter the data that you collect. All measured values must be

accompanied by the units of measurement (eg. mL, g).

When you will need to subsequently use a measured quantity in a calculation,

have that calculation ready with blanks to accept the measured quantity.

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Together, tables and calculations might look like the following:

Table 1. Masses of water-free primary-standard-grade KHP

Sample # Mass KHP (g) Moles KHP (mol)

1

2

3

4

Sample Calculation showing moles of KHP used

moles of KHP weighed out=massKHP/FWKHP=______g/204.22g/mol= _____ mol.

Once you have measured data, fill in the blanks. You need fill in only one sample

calculation for repeated trials, but the table will hold all replicate values.

Have a section that includes your observations such as “The bromocresol green

indicator color transition was difficult to detect” or “The stock sodium hydroxide

solution had an insoluble precipitate at the bottom that was filtered before use”.

If your laboratory is equipped with temperature, humidity and atmospheric

pressure sensors, you must record these values. “Room temperature” in Hawaii is

not necessarily the same as in Rhode Island.

Summary of Results and Conclusions: Write a brief but clear summary of your

results.

Laboratory Report Questions: Answer the questions as concisely as possible, and

be sure to cite any peer-reviewed scientific-quality references (not Wikipedia) that

you have used in determining your answer.

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September 18, 2010.

Jason R. Dwyer TA: Brian Kite, Tuesday 11am

Lab conditions: 23.0°C, 101.3kPa.

Standardization of ~0.1M sodium hydroxide (NaOH) with potassium hydrogen phthalate (KHP)

Source: University of Rhode Island CHM 212 Student Manual, 2010-2011.

Introduction/Background Information:

Equation 1: Balanced reaction of potassium hydrogen phthalate with sodium hydroxide

CO2K

CO2H

+ NaOH

CO2K

CO2Na

+ H2O

Materials:

Include chemical product and lot numbers when available. Include molecular weights, densities

and other properties when needed for the experiment or calculations. Units of measurement must

be reported for all quantities requiring them. Use proper chemical names before introducing any

abbreviations, other than the standard abbreviations for units.

Table 1: List of chemicals, their properties and amounts for the experiment.

Chemical Product No. Lot No. Density (g/mL) Mol. Wt. (g/mol) Amount needed

50 wt % sodium

hydroxide

mL

Potassium hydrogen

phthalate (KHP)

g

…

MSDS Highlights:

You should be familiar with the MSDS sheet in its entirety, but note principal health and safety

concerns here for every chemical used. Make sure to note carcinogenicity, teratogenicity,

mutagenicity, explosivity, flammability, inhalation hazards etc. If there are no special notes

to make, write “No special precautions required” and realize that means that you must still take

precautions such as all of your personal protective equipment and careful work habits. Use

proper names in this section.

50 wt % sodium hydroxide: Corrosive, avoid contact with skin & eyes—rinse with copious amounts of water if

contact occurs and seek medical attention. Avoid water, acids, organic materials, chlorinated solvents, aluminum,

phosphorus, tin/tin oxides, zinc.

…

Prelab Questions

1. The left-hand side of your lab book is for rough work

only. The right-hand side is your permanent record.

No information should be recorded on paper towels,

scraps or loose sheets of paper.

2. All work must be in permanent ink.

3. Any figures or data that you glue into your lab book

should be signed and dated with half the writing on

the inserted page and half the writing on the lab

book page.

4. Any mistakes are corrected with a single line through

the mistake and then your initials and the current

date written over top.

2

Answer any pre-lab questions here.

Procedure:

The procedure must be clear and accurate (it should be comprehensible to someone with chemical

training), but need not specify standard procedures that would be clear to someone with chemical

training. You substitute a flow chart in place of this numbered procedure. It is useful to draw

a vertical line 2/3 of the way across the page. Write your expected procedure only up to the

line and then note any changes you make on the day of the experiment on the other side of the

line. If no changes are made, write “No changes made to procedure”. Note here any observations

important for the experiment.

1. Dry KHP for 1h at 110°C, cool to room temp. in dessicator

2. Dilute 12mL [you must calculate the correct value] of

50wt% NaOH in 1L Class ___ volumetric flask with cooled, boiled (5

min) distilled water to produce ~0.1M NaOH aqueous solution.

3. Titrate ~0.51g aliquots of KHP with ~0.1M NaOH in replicate

using 3 drops of phenolphthalein indicator in each aliquot.

4. …

Sept. 18, 2010. No changes

made to procedure.

Results:

Label clearly all tables and figures so that anyone could look at just the table and caption and

understand it. The clarity of your titles/captions will be a substantial part of your report

mark. These tables should be ready to accept experimental values on the day of the experiment.

If you don’t perform one of your trials, write “Did not perform” and draw a line from there until

the end of the table.

Table 2: Titration of distilled water blanks with ~0.1M NaOH using phenolphthalein indicator

Trial # Start buret volume (mL) End buret volume (mL) Volume NaOH added (mL)

1

2

3

4

Mean

Std. dev.

Table 3: Titration of KHP aliquots with ~0.1M NaOH using phenolphthalein indicator

Trial # Mass empty

weigh boat (g)

Mass boat +

KHP (g)

Mass

KHP (g)

Start buret

volume

(mL)

End buret

volume (mL)

Volume

NaOH

added

(mL)

Blank-

adjusted

NaOH

volume

(mL)

1

3

2

3

4

Mean

Std. dev.

Calculations:

This is the first lab book section that does not need to be prepared in advance. Show sample

calculations with sufficient detail to make clear what you’ve done: it is useful to include a

sample calculation in words, first. Include relevant chemical equations (or reaction

stoichiometry) to provide the basis for your calculations; they may have already been included at

the beginning of your report.

Sample calculation 1: Calculation of standardized [NaOH]

From Equation 1:

[NaOH]=massKHP/VKHP×…=0.5103g/…=0.1001M.

Conclusions/Summary of Results:

Table 4: Results of standardization of ~0.1M NaOH with KHP using phenolphthalein indicator

Trial # [NaOH]

1

2

3

4 Did not

perform

Mean

Std. dev.

Make sure you have the correct number of significant figures here, especially!

The standardized concentration of the sodium hydroxide solution is ______±_____M (3 replicates).

Questions

Answer any post-lab questions here.

---End of regular lab report---

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Further examples of labeling figures. Your goal should be making clear the meaning and

significance of the figures to someone looking just at the figures. Your plots should instantly

show all of your data including your confidence in your measurement (your error bars), explain

any additions such as lines of best fit or of convenience. Your captions should explain the

meaning of the figure so that after reading it, I should be able to understand your plot. For

your convenience it is recommended that you use a computer graphing program such as Excel to

prepare plots. For labeling points or highlighting features on the plots, however, you may find

it easier to do so by hand after printing out the plot, and that is acceptable.

From Cheley et al., Chemistry & Biology (2002) 9, 829.

This figure meets the following requirements:

1. Plot axes meaningfully labeled and units are shown. The figure capture defines the

meaning of the variable names.

2. The figure caption explains what the figure means in terms of the experiment.

In your plots, I would also like to see:

1. Error bars added to the data points:

a. If you are plotting a mean, the error bars will be a function of the standard

deviation.

b. If you are plotting an experimentally measured single value, the error bars are

given by the experimental uncertainty.

c. It is normally preferable for each data point to be plotted with its own error

bars, but if the error is constant for all values, a single representative error

bar may be plotted and its universality noted in the figure caption.

2. Explanation of lines connecting points:

a. Is the line a line of best fit? If so, include the equation of the line and the

measures of the quality of the fit either on the plot or in the figure caption.

b. Is it a line “to guide the eye”—then note that in the figure caption.

c. If you do not have a line of best fit and you want to connect your points, you

should automatically default to connecting the points with a straight line. Do

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not choose a spline or other curved fit unless you have sound physical reasons for

it.

From Nablo et al., Biophys J (2008) 95, 1157.

This plot nicely shows the use of error bars and adds a dashed line to highlight an important

feature of the plot. It would be better to first introduce PEG as “polyethylene glycol (PEG)” ,

to have the x-axis labeled “Molecular Mass of PEG (g/mol)” and to have the y-axis labeled “Ratio

of currents with and without PEG: I(+PEG)/I(-PEG)”. Finally, the line joining the points should

be described: is it a line of convenience or is it based on a physical model?