16 . E
When an acid loses a proton it becomes its conjugate base. A conjugate acid is defined as the
acid formed when the base gains a proton.17 . B
pOH is a measure of hydrogen (OH–) ion content of an aqueous solution. It is defined as the
negative log of the hydroxide ion concentration.
18 . A
Within the same volume, an increase in the reactant concentration will increase the number of
times molecules bump into each other (elastic collisions) and will increase the rate of effective
collisions.
19 . D
Catalysts increase the rate of a reaction by decreasing the activation energy.
20 . B
An increase in temperature will add energy to the system and will therefore increase the
average kinetic energy.
21 . D
∆G is the energy of a system available to do work. A negative ∆G denotes a spontaneous
reaction, while a positive ∆G denotes a nonspontaneous reaction.
22 . A
An endothermic reaction absorbs heat from its surroundings as the reaction proceeds and has
a +∆H.
23 . C
See the explanation to question 21.
24 . E
The change in Gibbs free energy (∆G) can be determined for a given reaction from the
equation ∆G = ∆H – T∆S.