CH 361/CH 361H
Name ______________________________
Prelab #8
Due in class Tuesday, Dec. 1 (T/R section) or Wednesday, Dec. 2 (W/F) section.
**This prelab has two pages**
1. The isomerization reaction of 2,3-dimethyl-1-butene to 2,3-dimethyl-2-butene is carried out in
a sealed ampoule in the presence of an acid catalyst. When an equilibrium mixture is achieved,
the ampoule is removed from the heating block, chilled on ice, and then analyzed by GC. Given
the data in the table below, calculate the equilibrium constant for this reaction at each
temperature listed.
heat
“1-ene”
“2-ene”
Temperature
(oC)
% area 1-ene
(by GC)
% area 2-ene
(by GC)
73.4
14.24
85.76
145
20.72
79.28
291
37.93
62.07
Keq
2. Calculate Go for the isomerization reaction at 145oC. Show your work below.
3. Given the data listed in #2 above, explain how you would go about calculating Ho and So
for the isomerization reaction (Hint: this was discussed in lecture during Week 8).
4. In a different experiment, you measure the equilibrium constant for a certain reaction. You
carry out the reaction 6 times, and your data yields the following values for Keq: 116, 114, 135,
118, 121, 119.
a) Perform the Q-test to determine if any value is discordant. Show your work.
b) Calculate the mean of these numbers.
c) Calculate the estimated standard deviation, Sm, of the mean.
d) Calculate the 95% confidence interval of this data, . (use the 2-sided P2 values in the
Student t table). Show your work.
e) Report your result (i.e., the value of Keq) using the proper format. (Hint: this was described
in lecture during Week 9).