Free Practice Quiz Question List

10/14 Chemical Kinetics Online Quiz Questions

Use this free practice quiz with 20 questions to review 10/14 Chemical Kinetics, test your knowledge, and prepare for your next test or exam.

20 questions

True or false

1 point

True or false: A thermodynamically favorable reaction must also occur rapidly under the same conditions.

A
True
B
False

Choose one

1 point

For the reaction 2HI(g) → H₂(g) + I₂(g), HI disappears at 0.040 M s⁻¹. What is the reaction rate?

A
0.010 M s⁻¹
B
0.020 M s⁻¹
C
0.040 M s⁻¹
D
0.080 M s⁻¹

Choose one

1 point

Initial-rate data for A + B → products show that doubling [A] doubles the rate, while doubling [B] quadruples the rate. Which rate law is consistent with these observations?

A
rate = k[A]²[B]
B
rate = k[A][B]
C
rate = k[A][B]²
D
rate = k[A]²[B]²

Choose all

1 point

Select all statements that correctly describe a first-order reaction.

A
For a first-order reaction, ln[A] versus time is linear.
B
For a first-order reaction, [A] versus time is always linear.
C
For a first-order reaction, the half-life is independent of the initial concentration.
D
For a first-order reaction, the slope of 1/[A] versus time is −k.

Written response

1 point

What term describes the rate of a reaction at one particular moment, corresponding to the slope of a concentration-versus-time curve at that moment?

Fill in the blank

1 point

In a multistep mechanism, a species formed in one step and consumed in a later step is an . Adding all elementary steps gives the .

True or false

1 point

True or false: For a reversible reaction, adding a catalyst changes the equilibrium constant because it lowers the activation energy.

A
True
B
False

Choose one

1 point

What are the units of the rate constant for a reaction with overall order 2?

A
M s⁻¹
B
s⁻¹
C
M⁻² s⁻¹
D
M⁻¹ s⁻¹

Written response

1 point

A first-order reaction has k = 0.0250 s⁻¹. Calculate its half-life to the nearest 0.1 s. Enter the value in seconds; answers within ±0.05 s are accepted.

Fill in the blank

1 point

For the elementary step A + B → products, the step is , and its rate law is .

Choose all

1 point

Select all conditions required by collision theory for a collision to produce products.

A
The particles collide.
B
The collision has sufficient energy to overcome the activation barrier.
C
The particles have identical masses.
D
The particles have a suitable orientation for bonds to break and form.

Open ended

1 point

What two conditions must a proposed multistep reaction mechanism satisfy to be consistent with experimental observations?

Choose one

1 point

An uncatalyzed pathway has Ea = 80 kJ mol⁻¹, while a catalyzed pathway has Ea = 45 kJ mol⁻¹ at the same temperature. Which conclusion follows from the Arrhenius equation?

A
The catalyzed reaction has a smaller rate constant because its barrier is lower.
B
The catalyzed reaction has a larger rate constant because its barrier is lower.
C
Both reactions have the same rate constant because temperature is unchanged.
D
The catalyst changes ΔH, which directly determines the rate constant.

Choose one

1 point

For the reaction 2A + B → 3C, which expression correctly represents the reaction rate when concentration changes are measured over the same time interval?

A
The rate must be written only from the reactant whose concentration decreases fastest.
B
The concentration change for each species must be divided by its stoichiometric coefficient, with a negative sign for reactants.
C
The concentration change for each species must be multiplied by its stoichiometric coefficient.
D
Only product concentrations can be used to define a reaction rate.

Choose one

1 point

For a reaction $A+B\rightarrow\text{products}$ , doubling $[A]$ while keeping $[B]$ constant doubles the initial rate. Doubling $[B]$ while keeping $[A]$ constant quadruples the initial rate. Which rate law is supported by these observations?

A
$\text{rate}=k[A][B]$
B
$\text{rate}=k[A]^2[B]$
C
$\text{rate}=k[A][B]^2$
D
$\text{rate}=k[A]^2[B]^2$

Choose one

1 point

Which statement correctly identifies the linear plot and slope for a first-order reaction?

A
$\ln[A]$ versus time is linear, and its slope is $-k$ .
B
$[A]$ versus time is linear, and its slope is $-k$ .
C
$1/[A]$ versus time is linear, and its slope is $-k$ .
D
$[A]^2$ versus time is linear, and its slope is $+k$ .

Choose one

1 point

A reversible reaction reaches equilibrium more quickly after a catalyst is added, but the equilibrium composition remains unchanged. Which explanation is most appropriate?

A
It increases the enthalpy change of the reaction.
B
It changes the final equilibrium composition.
C
It changes the overall stoichiometric equation.
D
It lowers the activation energy through an alternative pathway.

True or false

1 point

True or false: On a reaction-energy diagram, the forward activation energy and $\Delta H$ are both determined by comparing the products directly with the reactants.

A
True
B
False

Written response

1 point

For 2HI(g) → H₂(g) + I₂(g), HI disappears at 0.040 M s^-1. What is the reaction rate? Enter the value in M s^-1.

Written response

1 point

A first-order reaction has a rate constant of 0.0250 s^-1. What is its half-life? Enter the value in seconds, rounded to three significant figures.