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WorksheetsAP Chem Unit 5 Kinetics Review
Total questions: 30
Worksheet time: 45mins
A catalyst increases the rate of a chemical reaction by:
Increasing the temperature of the reaction mixture
Providing an alternative reaction pathway with a higher activation energy
Being consumed in the reaction
Lowering the activation energy of the reaction
The rate of a certain reaction is given by the expression Rate = k[A][B]^2. If the concentration of B is doubled, the rate of the reaction will:
Remain the same
Double
Quadruple
Octuple
A reaction has a rate constant (k) of 2.5 x 10^-3 s^-1 at 25°C. If the activation energy is 75 kJ/mol, what will be the rate constant at 35°C?
2.5 x 10^-3 s^-1
Greater than 2.5 x 10^-3 s^-1
Less than 2.5 x 10^-3 s^-1
Cannot be determined without additional information
For the reaction A → B, the rate decreases over time because:
The concentration of A decreases
The concentration of B increases
The activation energy increases
The temperature of the system decreases
The half-life of a first-order reaction is independent of:
Temperature
Initial concentration of reactant
Activation energy
Presence of a catalyst
The mechanism of a reaction is determined by:
The balanced chemical equation
The activation energy
The rate law
The change in enthalpy
For a certain reaction, the activation energy is 56 kJ/mol. If the temperature is increased from 300K to 310K, what will happen to the rate constant (k)?
It will increase
It will decrease
It will remain constant
Cannot be determined without additional information
In a reaction, the rate is directly proportional to the square of the concentration of reactant A. This indicates that:
The reaction is zero order in A
The reaction is first order in A
The reaction is second order in A
The reaction order cannot be determined
A reaction has a rate law of Rate = k[A]^2. If the concentration of A is quadrupled, the rate of the reaction will:
Double
Quadruple
Increase sixteen times
Remain the same
The rate constant of a reaction doubles for every 10°C rise in temperature. This behavior is indicative of:
A low activation energy
A high activation energy
A catalyst present in the reaction
A reversible reaction
For a zero-order reaction, the concentration of the reactant:
Has no effect on the rate of reaction
Is directly proportional to the rate of reaction
Is inversely proportional to the rate of reaction
Increases as the reaction proceeds
The activation energy of a certain reaction is 100 kJ/mol. If a catalyst is added, which of the following is likely true?
The activation energy will increase
The activation energy will decrease
The activation energy will remain the same
The reaction will become endothermic
Which of the following will not increase the rate of a chemical reaction?
Increasing the temperature
Increasing the concentration of reactants
Adding a catalyst
Decreasing the surface area of solid reactants
A reaction's rate law is determined to be Rate = k[A]^3[B]^2. Which of the following statements is correct?
The reaction is third order in A and second order in B
The reaction is fifth order overall
The reaction is second order in A and third order in B
Both (A) and (B)
In a chemical reaction, the rate constant k has units of M^-1s^-1. This suggests that the reaction is:
Zero order
First order
Second order
Third order
The rate of a reaction can be expressed as the change in concentration of a reactant over time. Which of the following units is appropriate for the rate of reaction?
M/s
s/M
M^2/s
s/M^2
Which factor would not affect the rate of a gas-phase reaction?
Pressure
Catalyst
Volume of the container
Color of the reactants
In a reaction mechanism, an intermediate:
Is only formed in the rate-determining step
Is formed and consumed during the reaction
Is present in the final product
Is used up before the rate-determining step
The collision theory of chemical kinetics states that for a reaction to occur, reactant particles must collide:
With sufficient energy and proper orientation
With maximum energy regardless of orientation
Infrequently but with high energy
Frequently and with any energy level
For a certain first-order reaction, the half-life is found to be 2 minutes. After 6 minutes, what fraction of the reactant will remain?
1/8
1/4
1/2
3/4
A reaction is found to have a rate that is directly proportional to the concentration of reactant A and inversely proportional to the concentration of reactant B. The rate law for this reaction is most likely:
Rate = k[A][B]
Rate = k[A]/[B]
Rate = k[A]^2[B]
Rate = k[A][B]^2
The Arrhenius equation relates the rate constant of a reaction with:
Concentration of reactants
Activation energy and temperature
Pressure and volume
The presence of a catalyst
In a chemical reaction, if the rate of appearance of product P is 0.025 M/s, the rate of disappearance of reactant R in the reaction R → P is:
0.025 M/s
0.050 M/s
0.0125 M/s
Cannot be determined without the stoichiometry of the reaction
MgCO3(s) + 2HCl(aq) --> MgCl2(aq) + H2O(l) + CO2(g)
A student is studying the kinetics of the reaction represented above. In two separate trials, the student places a 0.95 g sample of MgCO3(s) in excess HCl(aq) and records the time required for the reaction to go to completion. In trial 1, the sample is a single piece of MgCO3(s). In trial 2, the sample consists of powdered MgCO3(s).
Which of the reactions is expected to have the longer reaction time, and why?
The reaction in trial 1, because the reaction occurs at a lower rate
The reaction in trial 1, because the reaction occurs at a higher rate
The reaction in trial 2, because the reaction occurs at a lower rate
The reaction in trial 2, because the reaction occurs at a higher rate
Zn(s) + 2HCl(aq) --> ZnCl2(aq) + H2(g)
The reaction between Zn(s) and HCl(aq) is represented by the equation above. In a kinetics experiment, a 0.15 g sample of powdered Zn(s) is added to an Erlenmeyer flask containing 100 mL of 1.0 M HCl(aq) at 25 degrees C. The rate of the reaction is determined by measuring the volume of H2(g) produced every five seconds.
Which of the following experimental changes is most likely to increase the rate of H2(g) production?
Using a 0.15 g sample of Zn(s) pellets instead of powdered Zn(s)
Using 150 mL of 1.0 M HCl(aq) solution instead of 100 mL
Using a 2.0 M solution of HCl(aq) instead of a 1.0 M solution
Cooling the HCl(aq) solution to 20 degrees C before adding the Zn
At a certain time during a reaction, the rate of disappearance of substance X was 4.0 x 10^-3 M s^-1, and the rate of disappearance of substance Y was 1.2 x 10^-2 M s^-1. At the same time, the rate of appearance of substance Z was 8.0 x 10^-3 M s^-1.
Which of the following represents the stoichiometry of the reaction?
X + 2Y --> 4Z
X + 3Y --> 2Z
2X + 3Y --> Z
4X + Y --> 2Z
The rate law for a particular reaction is rate = k[XY]^2. In an experiment, the initial rate of the reaction is determined to be 0.16 mol/(L*s) when the initial concentration of XY is 0.40 mol/L.
What is the value of the rate constant, k, for the reaction?
0.10 L/(mol*s)
0.40 L/(mol*s)
1.0 L/(mol*s)
2.5 L/(mol*s)
2 X(g) + 2 Y(g) --> Q(g) + 2 R(g)
The reaction represented above is found to be second order with respect to X and first order with respect to Y.
What happens to the rate of the reaction when [X] is halved and [Y] is doubled?
It increases by a factor of 4
It decreases by a factor of 2
It decreases by a factor of 4
It does not change
NO2(g) + NO3(g) --> N2O5(g)
The reaction represented above occurs in a single elementary step. The activation energy for the step is 18 kJ/mol, and the overall energy change is -136 kJ/mol.
What is the activation energy for the reverse step?
18 kJ/mol
118 kJ/mol
136 kJ/mol
154 kJ/mol
Which of the following best explains why the rate of a chemical reaction generally increases with increasing reactant concentration?
As concentration increases, the activation energy of the reaction decreases
As concentration increases, the average speed of the reactant particles increases
As concentration increases, the rate of collisions between reactant particles increases
As concentration increases, the overall energy change of the reaction decreases
