AP 5.5 Collision Model BANK

In the diagram above, where would the greatest number of successful collisions occur?

• To the left of the activation energy line.

• To the right of the activation energy line under curve T_1.

• To the right of the activation energy line under curve T₂.

What effect will increasing [H+] at constant temperature have on the reaction below?

Cl^-(aq) + ClO^-(aq) + 2H⁺ (aq) → Cl₂(g) + H₂O (l)

• The value of the rate constant will increase.

• The frequency of collisions between H⁺(aq) ions and ClO^-(aq) ions will increase.

• The activation energy of the reaction will increase.

• The activation energy of the reaction will decrease.

Lowering the temperature of a reaction will result in which of the following?

• a decrease in the mass of the molecules which causes fewer successful collisions.

• an increase in the number of successful collisions between molecules.

• a decrease in the concentration of reacting molecules.

• a decrease in the kinetic energy of the molecules which causes fewer successful collisions.

The energy needed by colliding molecules to break bonds.

• start up energy

• crash energy

• collision energy

• activation energy

Which curve on the diagram would produce more successful collisions?

• the red curve because it represents a lower temperature

• the purple curve because it represents a higher temperature

• the red curve because it represent a higher temperature

• the purple curve because is represents a lower temperature

A lower temperature in a lab would cause a reaction to slow for what reasons?

• more collisions between molecules and a higher concentration of molecules

• concentration of molecules would decrease and molecules would start to decay

• the molecules would decay at a slower rate and molecules would lose kinetic energy

• molecules would lose kinetic energy and there would be fewer collisions

For a collision to be successful, molecules must ..

• have enough kinetic energy and mass.

• never collide.

• have enough kinetic energy and the correct orientation.

• have the correct orientation and mass.

Cl⁻(aq) + ClO⁻(aq) + 2 H⁺(aq) → Cl₂(g) + H₂O(l)

What effect will increasing [H⁺] at constant temperature have on the reaction represented above?

• The activation energy of the reaction will increase.

• The activation energy of the reaction will decrease.

• The frequency of collisions between H⁺(aq) ions and ClO⁻(aq) ions will increase.

• The value of the rate constant will increase.

The gas-phase reaction A2(g)+B2(g)→2 AB(g) is assumed to occur in a single step. Two experiments were done at the same temperature inside rigid containers. The initial partial pressures of A2 and B2 used in experiment 1 were twice the initial pressures used in experiment 2. Which statement provides the best comparison of the initial rate of formation of AB in experiments 1 and 2 ?

• The initial rate of formation of AB is the SAME in both experiments because they were done at the same temperature and the frequency and energy of the collisions between A2 and B2 would have been about the same.

• The initial rate of formation of AB is SLOWER in experiment 1 than in with experiment 2 because at the same temperature, a higher pressure would reduce the volume available for A2 and B2 molecules to achieve the proper orientation for a successful collision.

• The initial rate of formation of AB is FASTER in experiment 1 than in experiment 2 because at a higher pressure the collisions between A2 and B2 molecules would have been more frequent, increasing the probability of a successful collision.

• The initial rate of formation of AB is FASTER in experiment 1 than in experiment 2 because at a higher pressure a larger fraction of the A2 and B2 molecules would have the minimum energy required to overcome the activation energy barrier.

Which of the following best helps explain why an increase in temperature increases the rate of a chemical reaction?

• At higher temperatures, reactions have a lower activation energy.

• At higher temperatures, reactions have a higher activation energy.

• At higher temperatures, every collision results in the formation of product.

• At higher temperatures, high-energy collisions happen more frequently.