[CHM 112] Lab Preparation

[Andrew J. Pounds]

When you come to lab tomorrow please have ENOUGH information in your lab 
notebooks to enable you to complete the lab.  Unlike some other 
professors, I do not require you to write the entire procedure in your 
lab notebook.  I do expect you, however, to have enough information in 
your lab notebook so that you can do the lab without having to ask for 
"procedural" assistance from Brook on "what to do".   Understand, it 
doesn't have to be anything elaborate -- but it does need to be 
reasonably complete.

For example, tomorrows notebooks might look like this:

*Pur**e solid: (part 1)*

 1. Set up ringstand and burner with 400ml beaker to make hot water bath.
 2. Use toploading balance to mass approximately 25 g of
    paradichloribenzene (read mass to 0.01 g)
 3. Quantitatively transfer paradichlorobenzene to the test tube,
    attache test tube to clam
 4. Lower into water and start heating.
 5. Once solution melts, remove it from heat, affix stopper with stirrer
    and thermometer
 6. Watch the temperature, once it falls to 60 degrees start stirring
    slowly and record the temp every 30 seconds
 7. Once the solution is difficult to mix (or once you have four
    sequential temperatures that are identical) stop the experiment
 8. Repeat 4 through 7 and collect the second set of pure solid data.

*Adding unknown solid (part **2**)*

 1. Use toploading balance to mass approximately 3 grams of unknown (
    read mass to 0.01 g)
 2. Quantitatively transfer massed unknown solid to test tube containing
    paradichlorobenzene.
 3. Do 4 through 8 of part 1 (now with the unknown solid included) to
    collect two sets of data.

*A**dding more unknown solid (part 3)*

 1. Use toploading balance to mass approximately 3 more grams of unknown
    ( read mass to 0.01 g)
 2. Quantitatively transfer massed unknown solid to test tube containing
    paradichlorobenzene and previously massed unknown.
 3. Do 4 through 8 of part 1 (now with approximately 6 g of solid
    included) to collect two sets of data.

*Clean-Up*


 1. Re-melt the solution in the hot water bath located in the fume
    hood.  Pour the solution in to the labelled waste container.
 2. A small amount of acetone may be used to dissolve whatever is left
    in the test tube.
 3. Return checked out components to stockroom and clean up lab space.



Brooke and I will be checking notebooks at the beginning of lab 
tomorrow.  Please have them open on the benchtops at the beginning of 
lab so we can do this quickly. Those who are not prepared will be asked 
to leave until they can show that they are ready for lab with a prepared 
notebook.  Your partners will be very upset with you if you have to do 
this...


-- 
Andrew J. Pounds, Ph.D.  (pounds_aj at mercer.edu)
Professor of Chemistry and Computer Science
Mercer University,  Macon, GA 31207   (478) 301-5627
http://faculty.mercer.edu/pounds_aj

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