Reaction Rates
Practice Test
1.
The exponents in a rate-law expression define the __________, which describes how the rate is affected by the concentration of the reactant.
a.
instantaneous rate
b.
reaction order
c.
concentration
d.
specific rate constant
2.
The term that describes the change in the concentration of a reactant divided by the change in time of the reaction is the ____________.
a.
average reaction rate
b.
activated complex
c.
rate constant
d.
chemical reaction
3.
What is the most common experimental method for evaluating a reaction order called?
a.
method of initial rates
b.
method of experimental rates
c.
method of instantaneous rates
d.
method of final rates
4.
Automobiles use a catalytic converter made of metal to ensure complete combustion of gasoline. What type of catalyst is present in automobiles?
a.
ephemiral catalyst
b.
homogeneous catalyst
c.
solid-state catalyst
d.
heterogeneous catalyst
5.
The rate law for the reaction between nitrogen monoxide and hydrogen is Rate = k[NO
2
]2[H
2
]. What happens to the rate if the concentration of nitrogen doubles?
a.
The rate is reduced by half.
b.
The rate quadruples.
c.
The rate doubles.
d.
The rate triples.
6.
Use the data in the table to calculate the average reaction rate expressed in moles H
2
consumed per liter per second.
Time (s)
[H
2
] (M)
[Cl
2
] (M)
[HCl] (M)
0
0.03
0.05
0.55
10
0.005
0.025
0.05
a.
0.002 mol/(L s)
b.
0.0025 mol/(L s)
c.
0.030 mol/(L s)
d.
0.003 mol/(L s)
7.
What are the units that generally express a reaction rate?
a.
moles per liter per second
b.
seconds per mole per liter
c.
seconds per liter per mole
d.
liters per mole per second
8.
Use the data in the table to calculate the average reaction rate expressed in moles HCl produced per liter per second.
Time (s)
[H
2
] (M)
[Cl
2
] (M)
[HCl] (M)
0
0.03
0.05
0.55
10
0.005
0.025
0.05
a.
0.0500 mol/(L s)
b.
0.005 mol/(L s)
c.
0.002 mol/(L s)
d.
0.0025 mol/(L s)
9.
When the concentration of a reactant is increased, the _______________.
a.
reaction stops
b.
reaction slows down
c.
reaction rate does not change
d.
reaction speeds up
10.
Use the data in the table to determine how long it will take to completely consume 1L of 1M butyl chloride [C
4
H
9
Cl], assuming the same reaction rate.
Molar Concentration of [C
4
H
9
Cl]
[C
4
H
9
Cl]
at t= 0.00 s
[C
4
H
9
Cl]
at t= 4.00 s
0.220M
0.100M
a.
3.00 s
b.
0.0300 s
c.
0.300 s
d.
33.3 s
11.
A substance that speeds up the reaction rate but is not consumed in the reaction is a(n) ____________.
a.
product
b.
reactant
c.
inhibitor
d.
catalyst
12.
What is the name given to a chemical produced in one elementary step and used up in a subsequent elementary step?
a.
elementary step
b.
reaction mechanism
c.
intermediate
d.
complex step
13.
What quantity is defined by the change in concentration of a component in a chemical reaction divided by the change in time of the reaction?
a.
rate order
b.
instantaneous rate
c.
specific rate constant
d.
catalyst
14.
What is the term given to a temporary arrangement of atoms that may produce either products or reactants?
a.
transition state
b.
activation energy
c.
collision
d.
reactant
15.
What are the individual steps in a complex reaction known as?
a.
elementary steps
b.
intermediate steps
c.
complex steps
d.
rate-determining steps
16.
What happens to the activation energy of the reaction when a catalyst is present?
a.
The activation energy does not change.
b.
The reaction stops.
c.
The activation energy decreases.
d.
The activation energy increases.
17.
What is the instantaneous rate for a reaction that is second order in A and first order in B when [A] = 2
M
and [B] = 3
M
? The specific rate constant for the reaction is 0.1
M
-2s-1.
a.
12
M
/s
b.
0.012
M
/s
c.
1.2
M
/s
d.
0.12
M
/s
18.
What will happen when you decrease the surface area of a reactant?
a.
The reaction slows down.
b.
The reaction rate does not change.
c.
The reaction speeds up.
d.
The reaction stops.
19.
How are the rate law and the order for a complex reaction determined?
a.
by trial and error
b.
by estimation
c.
by calculation
d.
by experimentation
20.
What is the reaction order for each reactant in the following rate-law expression? Rate = k[A][B]
2
[C]
3
a.
first order for A, first order for B, first order for C
b.
first order for A, second order for B, first order for C
c.
first order for A, second order for B, second order for C
d.
first order for A, second order for B, third order for C
