Chapter 4A Questions

Which of the following is required for a chemical reaction to proceed?

• Reactants collide

• Reactants collide in the correct orientation

• Reactants collide with sufficient energy

• All of the above.

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

• It increases the activation energy

• It decreases the activation energy

• It changes the reactants

• It is consumed in the reaction

Which factor does not affect the rate of a chemical reaction?

• Temperature

• Concentration of reactants

• Color of reactants

• Presence of a catalyst

What happens to the rate of reaction if the surface area of a solid reactant is increased?

• The rate decreases

• The rate remains the same

• The rate increases

• The rate becomes zero

The rate of a reaction generally increases with temperature.  The factor that has the biggest effect on the increase in reaction rate is that with increasing temperature…

• the activation energy of the reaction increases.

• the activation energy of the reaction decreases.

• the number of collisions between particles increases.

• the proportion of particles with high kinetic energy increases.

Zinc metal reacts with 0.1 M hydrochloric acid to form hydrogen gas and zinc chloride solution. The production of hydrogen gas is more vigorous if the zinc is powdered, rather than in large pieces, because the…

• activation energy of the reaction is lower.

• activation energy of the reaction is higher.

• frequency of collisions between zinc metal and hydrogen ions is higher.

• fraction of reactant particles with sufficient energy to react is higher.

When the gas pressure increases…

• the frequency of collisions decreases, the frequency of successful collisions decreases

• the frequency of collisions decreases, the frequency of successful collisions increases

• the frequency of collisions increases, the frequency of successful collisions decreases

• the frequency of collisions increases, the frequency of successful collisions increases

Which of the following would increase the rate of reaction?

• I only

• II only

• I and IV only

• II and III only

How does increasing the concentration of reactants affect the rate of a chemical reaction?

• The rate decreases

• The rate remains the same

• The rate increases

• The rate becomes zero

Which of the following statements is true about the effect of a catalyst on a chemical reaction?

• A catalyst increases the energy of the reactants

• A catalyst decreases the energy of the products

• A catalyst provides an alternative pathway with lower activation energy

• A catalyst is consumed in the reaction