Worksheet - Chapter 4
Chapter Problems: 35-38, 41-52, 54.
Additional exercises:
1. At 55 C the G for a given reaction is –20 kcal/mol.
If the H for the reaction is 16 kcal/mol, does the reaction have a favorable S? At what temperature would the
reaction become reactant favored? The H for the reaction is + 8 kcal/mol. Draw an
energy diagram of the reaction. Label the distance that represents the enthalpy of
reaction and activation. What would be the activation energy of the reverse reaction?
2. Construct an energy diagram of the reaction of A being converted to F. Label the
enthalpies of reaction of each step as well as the overall enthalpy of reaction and the
rate-determining step. Determine the energy of activation of the entire process. Give
the rate equation that you should see if the reaction followed the profile you have just
constructed. What is the probable molecularity of the reaction?
A
B
D
E
 B
+ C  D
 E
 F
Eact (kcal)
16
3
6
3
Ho (kcal)
5
-4
3
-12
3. The bromination and chlorination of trans-1-methyldecalin (trans-1methylbicyclo[4.4.0]decane) both give mixtures of products. Give the predominant
mono-brominated product for trans-decalin. The mono-chlorinated products are
numerous but there is a small surplus of one mono-chlorinated product. Identify it and
explain why it is in slight excess. Draw two more of the mono-chlorinated products.
Would spiro[4.5]decane have one mono-chlorinated product that is in surplus?
Explain.
4. The deprotonation of acetone by hydroxide ion (reaction below) is an endothermic
process. Will the Keq be larger or smaller than 1. Since it is an endothermic process,
+
O
OH
+
O
H2O
should the transition state look like reactants or products? Draw a structure of the
transition state that meets the requirements of the Hammond Postulate. The pKa’s of
acetone and water respectively are 20 and 16. Explain how this fits with the process
of being endothermic. The pKa of nitromethane (CH3NO2) is about 10. If you were
reacting nitromethane with hydroxide ion would the reaction be endothermic or
exothermic? Explain. Would the Keq be larger or smaller than 1? Draw the transition
state structure.