Ch 353L Laboratory Guidelines

CH 353L LABORATORY GUIDELINES

A. GENERAL CONSIDERATIONS

1. This set of labs was designed for the Physical Chemistry curriculum, and as much as possible, will parallel the lecture topics. The labs consist of pairs of matched wet and dry labs. The dry labs will consist of computer or data based projects that allow exploration and extension of concepts covered in the accompanying wet lab. The lab handouts will be made available in the week prior to the lab, or sooner if possible.

2. The wet labs will typically be done in groups, while the computer exploration labs will typically be done individually. The wet lab portion of the write-ups can consist of shared experimental data and analysis; however the dry lab portion should be the individual student’s work.

3. Each wet lab portion of the report is graded on a basis of 10 points. Maximum numbers of points deducted are as follows:

Introduction and Objectives / 2
Data / 2
Poor quality tables or graphs / 2
Results / 3
Sample calculations / 2
Neatness / 1
Discussion / 2
Poor English / 1
Each week (or fraction thereof) late / 1
Leaving a messy desk / 1

In some instances, a report may be sufficiently poor as to be returned to the student to be done again. In this instance there will be a late penalty.

4. To be able to execute an experiment within the three-hour time period, you must read the experiment and be ready to start when you arrive in lab. To encourage such activity, there is a set of questions related to each laboratory experiment to be answered before you enter the lab. Your answers should be neatly written out in full sentences on a clean piece of paper. To receive credit, hand in the answers to the questions in the laboratory report box before you start the experiment. The lab instructor will collect these at the beginning of the lab and credit of up to one point will be added to the grade for that experiment.

B. REPORT GUIDELINES

The portions of the report required for the wet and dry labs will be different. The dry lab write-ups should be written as a project report, and answer the specific questions in the lab handouts. The wet lab reports will consist of the carbon copies of your lab notebook (including a full discussion and conclusion). Each wet-dry pair of labs will also have a “module” assignment, where more open-ended questions pertaining to the theme of the wet and dry labs will be explored by the student.

The Laboratory Notebook: It is important that a scientist or engineer keep a detailed account of their work in the laboratory. The laboratory notebook should provide sufficient detail that someone else could reproduce your work and get the same results using your notebook as a guide. All experimental procedures, notes and data are to be kept in a bound notebook. Single sheets of paper are not allowed.

Your notebook should contain the following information and should be completed during the lab period:

1.   Date the experiment was conducted.

2.   Title of experiment.

3.   Introduction: Purpose and Objective of the experiment.

4.   Details of the procedure that you used.

5.   Careful record of all data measured, including units.

6.   Comments for conclusions: This section should make an assessment of how the experiment went. In particular, if errors or problems were encountered during the experiment, then they should be duly noted. Be realistic in your assessment of errors and don’t put down every possible place where something could go wrong. Also, if the results can be compared with known results, then this should be done.

7.   Signature of person performing the experiment and that of a witness, i.e. the instructor or the Teaching Assistant. The witness cannot be another student.

General Guidelines for Keeping a Laboratory Notebook:

1.   Make all entries in you lab notebook using indelible ink (NO PENCILS).

2.   Write in third person, past tense as though you are an objective observer.

3.   Do not remove any permanent pages from you notebook, only the yellow pages.

4.   Draw only one line through entry errors and write the correct information directly below.

5.   Sign and date your notebook at the end of each entry, i.e. at the end of each laboratory period, or writing period at home or office.

6.   Place a single diagonal line through any blank space in your notebook.

7.   Enter procedures, observations, data, etc. in your notebook as you do the experiment, not at a later time.

Properties of a Good Graph

·  The graph should have a title. The axes should be labeled and indicate units.

·  The variable you are adjusting is on the x-axis. The variable you are measuring or determining is on the y-axis.

·  The actual points are shown on the graph.

·  The size of the graph should be chosen so that features are easily visible and distinguished.

·  The scales (maximum and minimum values) of the axes should be chosen so that the points fill the whole graph.

Properties of a Good Table

·  The tables should have good descriptive titles and be numbered sequentially.

·  All columns and rows should be labeled. The labels should be recognizable by people unfamiliar with the experiment. That is, tube 1, or flask 2 is not acceptable.

·  The numbers should use the appropriate number of significant figures.

·  Units should be used consistently throughout. Make certain there are units on the variables especially in the headings on the columns and rows.

C. SAFETY AND DISPOSAL GUIDELINES

For experiments involving open chemicals, approved safety goggles must be worn at all times in the lab. This means instructors as well students. There will be separate waste disposal bottles for these experiments, and all chemicals used in the lab must be disposed of in the proper manner.

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