Laboratory Manual for Chem 201

Used as a Companion to Chemistry, 7th Edition, by Zumdahl & Zumdahl

Department of Chemistry

University of Nevada, Reno

Contributors: Heather S. Clewett and Jason Shearer

With thanks to Thomas Brown, Danil Kaliakin, Kelly Chen, & Kristy Peck, UNR Chemistry Department TAs, for significant assistance and feedback.

Contents

Introduction 3

About this Lab Course 3

Course Objectives & Philosophy 4

Necessary Supplies 4

Lab Management - Things You Need to Know to be Successful 5

Lab Requirements and Grading 6

Pre-Lab Requirements 7

In-Lab Requirements 9

Post-Lab Requirements10

Notes on Grading12

Experiment 1: Density Investigations13

Skill-Building Inter-session22

Experiment 2: Reactions with Copper (2 week lab)25

Experiment 3: Qualitative Analysis (2 week lab)39

Experiment 4: Titrations of Acids49

Experiment 5: Calorimetry and Thermodynamics58

Experiment 6: Redox Titration67

Experiment 7: Atomic Spectroscopy76

Experiment 8: Particle in a Box Simulations87

Appendix: Sample Lab98

About this Lab Course

Introduction

Welcome to Chem 201L!

Chem 201L is an inquiry-based lab course. In Chem 201L this semester, the students fundamentally assume ownership of the investigation; your TA will be a valuable resource but will not tell you what to do or how to do it. Instead, your TA will support you with guiding questions and may also recommend that you discuss your question(s) further with your group members. You will not be abandoned, but you will come to rely more on yourself and your peers, spending time and effort to think through the problem(s) you have encountered, rather than passively accepting an experts answer.

As a student in an inquiry lab, you will

have input in deciding the question to be investigated and the hypothesis statement.

write your own procedures.

create your own data tables.

analyze your data yourself, including looking up necessary formulas in your text.

compare your data and analysis with the class as a whole and actively exchange ideas with your fellow lab members to make sense of the data and any discrepancies.

write conclusions that provide answers to the beginning questions (these answers are also called claims) and explain how the evidence supports the claim, demonstrating your comprehension of both theory and how the data relates to theory.

be graded more on the quality of your thinking and writing than on whether or not you arrive at the right answer.

You will most likely also

make some mistakes (because you arent following a scripted right way of doing things).

Once again, inquiry-based labs are not focused exclusively on getting right answers. Answers in the science community commonly undergo modifications as more evidence comes to light, and a three-hour student lab is not expected to achieve the same degree of accuracy as years of research using high-precision instruments.

Course Objectives & Philosophy

One goal of this course is to prepare you to start undergraduate research. Expect to be challenged. Plan to be highly organized. Manage your time efficiently and complete lab write-ups promptly, while information is still fresh. Practice your best active reading and note-taking strategies as you read/study this lab manual. (These are the most common suggestions made by previous years Chem 201 students, in fact.)

Interaction with peers is encouraged and even necessary for completion of lab work. This is representative of professional chemical practices in industry and academia. Discussions are always encouraged; actual word choice should never be copied directly, of course.

Students will:

demonstrate safe laboratory practices and correct handling of equipment, supplies, and waste.

follow mainstream science conventions when reporting and interpreting data as well as when performing calculations.

exercise scientific ethics, including thorough individual preparation for lab experiments, use of bound lab notebooks and recording all data in ink.

demonstrate conceptual and practical understanding of chemical theories, practices and calculations pertinent to lecture topics.

Necessary Supplies

**Find the Lab Schedule for the day of the week that your lab meets. Print it out and refer to it throughout the semester. It will be your main guide for due dates of all lab assignments.

Use the lab schedule as a guide, but know that pre-lab and post-lab requirements will vary slightly with each lab (and some labs span 2 weeks). Read the instructions thoroughly for every lab and ask your TA questions any time you need clarification.

Visit WebCampus and print out the lab and any additional materials that will be useful to you, for each lab.

Additionally, you will need to purchase a carbon copy lab manual (these are available at many locations in town and online; 100 carbonless, graph-paper marked pages are recommended.) Your lab manual must be numbered and include a table of contents (you may add these by hand, if needed).

Bring a pen and calculator to every lab class. You may also wish to bring a ruler.

(Note that pre-lab and post-lab work may be completed in pencil, but all original data must be recorded in pen.)

Wear appropriate personal protective gear as described in the Lab Safety Assignment.

Lab Management - Things You Need to Know to Be Successful

Be prepared to spend an average of 3 hours per week outside of lab (in addition to the 3 hours per week spent in lab) working on lab assignments.

This lab complements the lecture; consistent attendance at lecture (and reference to both lecture notes and your textbook) will increase your performance in lab.

You will occasionally be dependent on other students results; you will not always be able to collect all your own data; cooperation and collaboration are part of the real world. Get to know your lab mates, and support one another.

Plan to consult with your lab mates and TA frequently. Ask questions! Share your ideas!

Failure to come prepared to lab in appropriate clothing, with safety goggles and completed pre-lab may prevent you from participating in lab, resulting in an automatic zero for that lab. This policy extends to late arrivals to lab, as well.

There are no make-up labs.

Lab Requirements & Grading

It doesnt count--and cant be graded--until its on paper.

Grading

Overview

All Lab Reports are to have all of the following Headings:

(Pre-lab)

Pre-lab Exercises

Original Beginning Question

Selected Question (Note: This will be determined as a result of whole class discussion.)

Hypothesis

Procedure

Safety Notes

(In-lab)

{possible adjustments to Procedure and Safety Notes}

Data, Observations & Calculations

(Post-lab)

Results

Claim(s)

Post-lab Question(s)

Reflection

The requirements for each of these headings are discussed more thoroughly on the following pages.

Also, please view the SAMPLE LAB provided in the Appendix (and also available on WebCampus) for a template/exemplar.

Pre-Lab Requirements

READ the laboratory description and any supplementary materials. Lab descriptions are dense; you need to spend quality time and practice active, thorough, close reading.

Complete the Pre-lab Exercises, as indicated in the laboratory description.

Construct a productive, Original Beginning Question (details for this process are provided below).

Consider the goals of the laboratory experiment and the suggested Beginning Question Seeds, provided on all lab experiments except Experiment 1, which instead provides the Beginning Question. Note how the Seeds address the Goals. You may refine one of the provided Beginning Question Seeds or synthesize a Beginning Question of your own.

Requirements for your own, Original Beginning Question:

It is your original creation or original spin on a Seed question.

It is a Productive question and lends itself to the creation of a testable hypothesis.

Examples of Productive Beginning Questions for Experiment #1:

What factors (phase, mass, instrument precision, etc.) hinder or improve accuracy of measurements?

How does the test sample volume of an unknown liquid affect the accuracy and/or uncertainty?

How does the accuracy of the density of air measurement vary with the number of syringe pumps used to evacuate the bell jar?

Examples of Non-productive Beginning Questions for Experiment #1:

Simplistic, single answer questions:

What is the density of air?

What is my unknown liquid?

What is the percent error in my calculation?

Procedural questions:

How do I use a pipet?

Why questions (can not be answered by performing the experiment):

Why are some materials more dense than others?

Hopefully, it is a question that you are personally interested in investigating.

Note that the ultimate choice of experiment will be driven by the class discussion of these Beginning Questions.

Contribute to your sections discussion of the Beginning Question; your TA will give you specific directions on when/how to discuss the Beginning Questions and finalize the Selected Question.

Pre-Lab Requirements, continued

It is each students responsibility to asce