CHEM 237 EXPERIMENT #10
The Chlorination of 1-Chlorobutane –GC Analysis
Post-lab Assignment - Spring 2010
Post-lab Questions: Answer these post-lab questions neatly and concisely on the
back of the lab report sheet. Use a blank sheet of paper if more space is needed
to answer these questions. Your answers will be evaluated and graded on
quality, not quantity of response! You are to complete this post-lab questions
assignment individually. You should work on this post-lab assignment as you
would work on a take-home examination. Write all responses in ink. Responses
written in pencil [in part or whole] will be accepted for a grade, but ANY and ALL
requests for a regrade will be denied. This also applies to responses written in
pencil and then overwritten in ink and/or responses obliterated with white-outtype materials and then revised.
Question #1: In Experiment #7, we analyzed a number of samples collected
from the distillation of a cyclohexane and toluene mixture. One sample was run
in order for you to calculate a response factor. Explain why in Experiment #7 a
response factor was needed but one was not needed in Experiment #10. 1.0
point
Question #2: How would you expect the relative response factors to differ
between the dichlorobutanes and 1-chlorobutane? What should have similar
response factors and what should have different response factors? 1.0 point
Question #3: Chlorine atoms [Cl] are know to stabilize radicals via resonance
as in the drawing below.
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Despite this resonance stabilization, 1,1-dichlorobutane was probably the minor
product of all of the dichlorobutanes. Based on the product ratios you
determined, factoring in statistics [the number of hydrogen atoms on each
carbon], ran the hydrogen atoms from least susceptible to most susceptible to
chlorination. Why is it not proper to cite stability of the intermediate radical when
referring to the product yield? 3.0 points
Some thoughts on answering post-lab questions
 In many of the post-lab questions, you will be asked to provide an answer
and an explanation for that answer. In the past, many students have written
prose explanations. When you are writing your explanations, you should
seriously think about explicitly including a chemical structure(s) and or a
chemical equation(s) in addition to the prose as part of your explanation.
Chemical structures and/or chemical equations can be used to add a great
deal of specific information to an explanation in a way that pure prose
cannot. In addition, chemical structures and/equations can make your
responses much each easier to understand.
 When you are writing your explanations for the post-lab questions, make sure
you include all necessary information. Do not answer a post-lab question with
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The TA can evaluate and grade only what you have written, not what is not
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 Audience: Even though a TA will evaluate and grade your post-lab question
responses, you should answer the post-lab questions as if you were providing
that explanation for a fellow organic chemistry I laboratory student. If a
fellow organic chemistry I laboratory student does not understand your
explanation, then you need to provide more specific information and/or
rewrite your response in a more understandable manner.
LABORATORY SAFETY
Any act of unsafe behavior, including failure to wear safety goggles whenever
any student is working, can result in dismissal from the lab. Students dismissed
from the lab for safety violations are eligible to take a make-up exam but a
portion [five (5)] points will be deducted from the score earned on the exam.
This safety announcement is not part of the Experiment #10 post-lab
assignment.
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Statement Box:
Signature _____________________________________________________