AP Chemistry Kinetics

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

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.

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

NGSS.HS-PS1-7

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.

Tags

NGSS.HS-PS1-5

NGSS.HS-PS1-6

If the equilibrium constant for a reaction is greater than 1, what does this indicate?

• The concentration of reactants is higher than that of products at equilibrium

• The concentration of products is higher than that of reactants at equilibrium

• The reaction does not reach equilibrium

• The reaction is exothermic

Define Le Chatelier's Principle and how it applies to chemical equilibrium.

• Le Chatelier's Principle suggests that equilibrium shifts are not influenced by changes in concentration, pressure, or temperature.

• Le Chatelier's Principle explains how systems at equilibrium respond to external disturbances by shifting the equilibrium position.

• Le Chatelier's Principle states that equilibrium cannot be disturbed by external factors.

• Le Chatelier's Principle explains how systems at equilibrium remain unchanged regardless of external influences.

Define the term 'equilibrium constant' and how it relates to chemical equilibrium.

• The equilibrium constant is the rate at which a reaction occurs

• The equilibrium constant is not affected by temperature changes

• The equilibrium constant is only applicable to reversible reactions

• The equilibrium constant relates the concentrations of products and reactants at equilibrium for a chemical reaction.

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

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.

Tags

NGSS.HS-PS1-5

Based on the data, what is the concentration of the substance after 60 s?

• 0.125 M

• 0.032 M

• Need to know the order of the reaction.

• 0.063 M

Answer explanation

The data shows the half life of the reaction is 10 s. Therefore, by dividing the concentration given by two a sufficient number of times, one finds the concentration at 60 s to be 0.063 M.

Tags

NGSS.HS-PS1-5