Chem 124: General Chemistry for the Engineering Disciplines

 

 

 

 

 

 
 
 
Lab Guidelines
 
     

The following sections are covered below:

Lab Manual and Lab Rules:

Chemistry is an experimental science and as a result, this class will incorporate laboratory activities into the curriculum. Most of the laboratory experiments can be found on the Chem 124 online laboratory manual.

Online Chem 124 Laboratory Manual

Links to the various lab activities are also provided on the Chem 124 homepage for your section.

You will be expected to follow the safety guidelines provided by the online laboratory manual. In addition to the rules in the lab manual you should also wear appropriate clothing to class on the days that we are performing a lab. Appropriate clothing includes shirts with sleeves (meaning shoulders are covered, no tank tops or spaghetti straps) and that completely cover one's torso (no bare midriffs), and you should also wear closed-toed shoes with a back (no slip-ons). If you are dressed inappropriately for lab, I will ask you to leave to change.

Laboratory Notebook:

The laboratory notebook is your place to record your laboratory work and to make an immediate and permanent record of your laboratory work. Your notebook must have carbonless copies so you can remove pages easily.

While recording your information in your notebook, use the following guidelines:

  • On the outside cover, print your name. On the inside front cover, print your identifying information (name, Chem 124 section, email address and phone number).
  • Reserve the first few pages for a Table of Contents. Depending on which lab notebook you buy, one may be started already for you.
  • Make all entries in non-erasable ink. If you make a mistake in writing a notebook entry, draw a single line through it and write the correct entry above it. NEVER whiteout or obliterate an entry, and never remove a page from you notebook.
  • If the pages are unnumbered, number the right-hand pages consecutively in their upper right corners.

Pre-Lab Format: (to be done before coming to class)

Before coming to lab, you should prepare your laboratory notebook. We will be checking your notebook to see that you have provided the necessary sections and are prepared to perform the laboratory. You should prepare your notebook the night before class as you read over the laboratory procedure. If you do your lab prep beforehand correctly, it should take you a little while (around an hour). You should read over the lab carefully and try to get a good idea of what is going on while you are doing your notebook prep. The following sections are required in your notebook BEFORE the laboratory experiment:

  • Title of experiment
  • Date of experiment
  • Names of lab partners
  • Purpose of the experiment - just a brief (usually one or two sentences, no more than a small paragraph) to describe the purpose of the experiment. (What is the goal of the experiment? What are we trying to learn?) This should be written in complete sentence form.
  • Procedure - write in your OWN words...DO NOT COPY the lab instructions or refer to the online lab manual! The procedure should be detailed enough so that that if the power went out in the room, you should still have enough details to complete the experiment and others can follow your procedure. I highly recommend using an outline form or a flow chart. The steps can be listed as simply as "Weigh out 5.00 g of water in styrofoam cup. Record initial temperature of water using Logger Pro."
  • Data and Observations Section - This is the most important section. Your data should be neatly organized and presented in a correctly labeled format in your notebook. If possible, organize your data section in tables. Note that a data table should be titled, columns should be clearly labeled and have units, and the correct (or requested) number of significant figures must be used. You should have data tables already set up in your lab notebook when you come to class that day. NEVER write data or observations on a separate piece of paper and then recopy them into your notebook. It may not be clear what data you will be recording, so read the lab manual carefully. If the manual says, "Weigh an empty styrofoam cup.", then one of your entries in the data table should be "Mass of cup".

The sections above should all be on the carbon copy that you will turn in after completing the data acquisition portion of the lab. I do not need to see calculations in your notebook, but feel free to use your notebook for sample calculations. We will be checking your carbon copies when you turn them in so please follow the instructions above.

Failure to have the above sections completed in your notebook ahead of time, failure to have your notebook in class the day of an experiment, or failure to turn in the carbon copies will result in points being deducted (up to 20%) from the final lab report grade for the experiment.

Lab-Report Form:

You are to turn in typed word document as your final lab report. A Microsoft Word file for each experiment will be posted on the course schedule page immediately following the experiment. You are to download this form and fill in the appropriate spaces. The following sections usually are included in your lab reports (unless otherwise specified):

  • Calculations - You need to show a sample calculation for each type of calculation you do for the experiment and include each step. Data tables can and should be used to summarize your calculations, but you will need to show how you got all the values in that data table unless the values came directly from the collected data. Don't forget to appropriate units and be aware of significant figures.
  • Graphs - (More information is available on the Graphs webpage) Most lab reports will require graphs. Each graph should be clearly and correctly labeled. Please note the following features of a good graph:
    · The title is descriptive and does not contain the word "versus".
    · The axes are labeled and include the appropriate units.
    · A scatter (rather than line or connect-the-dots) plot is used and a regression line added.
    · The equation and correlation coefficient for the regression line are shown but are away from other data.
    · The graph matches the data in terms of significant figures, as does the equation used to fit the data.

Graphs should be generated in a graphing program (like Microsoft Excel) and a printout can be pasted into your lab notebook so that you have a copy. You will need to make two copies of any graphs you generate - one for your original notebook and a second to turn in with your lab report. This latter copy must be inserted into the word document you turn in as your final report (stapling it to the back of the report is not sufficient).

  • Conclusions - A good lab report should always include a conclusion about the results of your experiment. Saying you enjoyed or hated the experiment is not a conclusion. There are three key features that should appear in a conclusion:
    1. You should state your final result that you were trying to determine by doing the experiment. Summarize concisely what conclusion you can make based on your experimental data. In some cases, you will be determining some measurement of an unknown. In other cases, you need to make a conclusion about a particular chemical trend or concept. If you wrote a good purpose of the experiment, it should help to guide you as to what is an appropriate conclusion.
    2. You should state a few short sentences about how you got that final result, but do NOT relive the entire procedure. Just a summary sentence or two should suffice.
    3. You should lastly state any errors that could have gone wrong to give you a value different that what is expected. If you make a technical error during the experiment that might affect your results, this is a good place to report that error and offer an explanation as to why your results may not be accurate and how the error would affect your result. Being able to analyze your mistakes is a valuable skill in problem solving.
  • Questions - For each lab, you will be assigned questions to answer. You are encouraged to discuss these questions with your laboratory partners, but you are to individually answer them in your own words and to answer them in complete sentences. Proper grammar and spelling are expected. If you have the same answer as a classmate, you will receive a zero on the assignment.