Cliffs AP Chemistry, 3rd Edition

Answer: D

Let Xbe what needs to be done to [B].

/

k

kXX

2

1 2

rate 4

rate

AB

AB

2

2

old

new

:

:

== =

_i

66

66

@@

@@

X= 2

3. Which of the following changes will decrease the rate of collisions between gaseous
   molecules of type A and B in a closed container?

A. Decrease the volume of the container.

B. Increase the temperature of the system.

C. Add A molecules.

D. Take away B molecules.

E. Add an accelerating catalyst.

Answer: D

With all other factors held constant, decreasing the number of molecules decreases the chance
of collision. Adding an accelerating catalyst has no effect on the rate of collisions. It lowers the
activation energy, thereby increasing the chance for effective molecular collisions. Furthermore,
it increases the rate of production.

4. For a certain decomposition reaction, the rate is 0.50 mole/liter ⋅sec when the

concentration of the reactant is 0.10 M. If the reaction is second order, what will the

new rate be when the concentration of the reactant is increased to 0.40 M?

A. 0.50 mole/liter ⋅sec

B. 1.0 mole/liter ⋅sec

C. 8.0 mole/liter ⋅sec

D. 16 mole/liter ⋅sec

E. 20. mole/liter ⋅sec

Answer: C

The concentration of the reactant is increased by a factor of 4, from 0.10 M to 0.40 M. If the
reaction is second order, the rate will then increase by a factor of 4^2 = 16.

..

1

16

1

050

1

80

liter sec

mole

liter sec

# moles

::=

Part II: Specific Topics