Kinetics AP Chemistry

What is the rate-determining step in a reaction mechanism?

• The step with the highest concentration of reactants

• The slowest step in the reaction mechanism

• The first step in the reaction mechanism

• The final step in the reaction mechanism

Tags

NGSS.HS-PS1-5

How does temperature affect the rate of a chemical reaction?

• Temperature decreases the rate of a chemical reaction.

• Temperature increases the rate of a chemical reaction.

• Temperature has no effect on the rate of a chemical reaction.

• Temperature only affects the color of a chemical reaction.

Tags

NGSS.HS-PS1-5

Define activation energy and its role in kinetics.

• Activation energy is the energy stored in the reactants

• Activation energy is the energy required for a reaction to stop

• Activation energy is the minimum energy required for a reaction to occur and influences the reaction rate by affecting the frequency of successful collisions.

• Activation energy is the energy released during a reaction

Tags

NGSS.HS-PS1-5

What is the half-life of a first-order reaction?

• t1/2 = 2k

• t1/2 = k / ln(2)

• t1/2 = 1/k

• t1/2 = ln(2) / k

Tags

NGSS.HS-PS1-5

What is the role of a catalyst in a chemical reaction?

• A catalyst changes the products of the reaction.

• A catalyst speeds up the reaction by lowering the activation energy barrier.

• A catalyst slows down the reaction by increasing the activation energy barrier.

• A catalyst has no effect on the reaction rate.

Tags

NGSS.HS-PS1-5

If a reaction is at equilibrium and the concentration of reactants increases, what happens to the reaction?

• The reaction will produce more reactants to reestablish equilibrium.

• The reaction will produce more products to reestablish equilibrium.

• The equilibrium position remains unchanged.

• The reaction will be unable to reestablish equilibrium.

Explain the concept of dynamic equilibrium in a chemical reaction.

• Dynamic equilibrium occurs when the reaction stops completely.

• Dynamic equilibrium means the reaction proceeds in only one direction.

• Dynamic equilibrium only happens in irreversible reactions.

• Dynamic equilibrium in a chemical reaction is when the rate of the forward reaction equals the rate of the reverse reaction, maintaining constant concentrations of reactants and products.

Tags

NGSS.HS-PS1-6

When the rate of consumption of iron (II) is 15.0 M/s, what is the rate of production of the manganese (II) ion?

• 3.0 M/s

• 15.0 M/s

• 5 M/s

• 24.0 M/s

Answer explanation

Rates of change are stoichiometric. Therefore, since iron (II) and manganese (II) are in a 5 mol: 1 mol ratio, manganese (II) is produced at a rate of 3.0 M/s at that instant.

Tags

NGSS.HS-PS1-5

NGSS.HS-PS1-7

A reaction is found to have the following mechanism, what is the order of the overall reaction with respect to substance A_2?

• 0th

• 1st

• 2nd

• 3rd

Answer explanation

The slow step for the mechanism is the first step. This means the rate law for this elementary step is equal to the overall reaction. The slow, elementary step has 1 for the coefficient for A_2; therefore, the reaction is first order with respect to A_2.