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Reminder: THE LAST DAY for undergraduates to drop a course is the end of the ninth week of classes, Friday, November 1, 1996.
The Illustrated Periodic Table experiment is titled "Periodic Properties of the Elements" in the manual.
The Lab Practical is a TEST SITUATION. There should be no talking during the laboratory period and the lab manual and the lecture textbook will not be allowed in the laboratory.
The following equipment or reagents will be available in the laboratory for you to identify the unknown solutions or solids.
You have observed at least one property of each possible unknown during the semester, so you should be able to look back through your notes and find a property that will unambigously identify the unknowns. You should be able to determine the identity of the unknowns with a few simple tests. Obviously, you should try to figure out which tests should be performed BEFORE coming to lab.
The sodas that will be available for this experiment are 7-Up and Diet 7-Up. You should look up the predominant acid contained in these drinks before coming to lab and include sample calculations for your titrations in the Pre-Lab Entry. The acid concentration will be determined on the basis of the predominant acid in the soft drink even if there is more than one acid present in the solution.
You should be prepared to observe the color of phenolphthalein in NaOH(aq) and the soda during the initial heating period.
A "quick and dirty" titration could be done before the careful titrations to approximate the volume of base required.
Common experimental errors include over-shooting the end-point or observation of air bubbles in the buret or buret tip. It is valid to not include data from trials where these errors are noted. However, remember to note the reason that a trail is not included in your notebook.
Questions: Does it suprise you that you drink acidic solutions? Can you think of other examples of drinks or food that might contain acids or bases?
In CH 104 , there are a large number of interesting water chemistry problems being investigated that require special precautions. Please make sure that you ask your TA or the Lab Director about any chemical you are uncertain about handling. We want you to enjoy the experience of a research project without encountering any catastrophic accidents.
Wearing sandals or open-toed shoes of any kind can cause you to be dismissed from laboratory.
Safety glasses are not appropriate eye protection in the laboratory. They do not protect your eyes from splashes. Safety goggles must be worn at all times in the laboratory. This requirement applies to Teaching Assistants as well as students, so tell your TA to wear them.
Graphing and Analytical Techniques, page 16 top. The metal pieces will not be stamped with a number, therefore you do not need to record the identity of your metal piece.
Diluting Solutions and Measuring Absorbance, page 22 near the bottom. The procedure indicates that you should measure the conductivity of 0.01 M KMnO4, but this solution will not be available. Please substitute "measure the absorbance of the stock solution."
Reaction Types and Chemical Logic, page 27 last paragraph. The manual states that there will be five unknowns, however there will seven unknown solutions in the unknown kit.
Spectroscopic Analysis of Wine, page 49 Part A. The directions under "Preparing a Sample" indicate that you should mix the cerium(IV) solution with the 20% ethanol solution, but you do not need to collect the spectrum of this solution. The spectrum of this solution is included in the manual on page 50. However, you will still need to collect the spectrum of the yellow ammonium hexanitrato cerium(IV) solution. There is no special preparation procedure for this solution. Simply place a small volume of the solution in the cuvet and collect the spectrum with the scanning spectrometer.
If you find an error in the manual, please contact me in Room 1317 in the Chemistry Building or send email to march@chem.wisc.edu.
Preparation and Properties of Aspirin and Some Flavoring Esters, page 62 third paragraph from the bottom. There is not a Part D to this experiment. However, you should schedule other activities while you wait for the bath to reach a constant temperature. One suggestion would be to begin working on the qualitative analyses. You could begin running the Ferric Chloride or Sodium Bicarbonate tests (page 64) on salicylic acid.
On page 63, second paragraph after figure1, the last sentence should read, "Use this value to determine the percent yield."
If you find an error in the manual, please contact me in Room 1317 in the Chemistry Building or send email to march@chem.wisc.edu.
A handout that contains the figures that are not complete in the Aspirin and Polymer labs will be distributed during the week of Nov. 11.
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