Chemical Reaction and Catalysts Quiz

Adding a catalyst to a chemical reaction results in:

• a decrease in activation energy and a decrease in the reaction rate

• a decrease in activation energy and an increase in the reaction rate

• an increase in activation energy and a decrease in the reaction rate

• an increase in activation energy and an increase in the reaction rate

A catalyst works by:

• increasing the potential energy of the reactants

• increasing the energy released during a reaction

• decreasing the potential energy of the products

• decreasing the activation energy required for a reaction

Which statement best explains the role of a catalyst in a chemical reaction?

• A catalyst is added as an additional reactant and is consumed but not regenerated.

• A catalyst limits the amount of reactants used.

• A catalyst changes the kinds of products produced.

• A catalyst provides an alternate reaction pathway that requires less activation energy.

Based on the nature of the reactants in each of the equations below, which reaction at 25°C will occur at the fastest rate?

• C(s) + O₂(g) → CO₂(g)

• NaOH(aq) + HCl(aq) → NaCl(aq) + H₂O(l)

• CH₃OH(l) + CH₃COOH(l) → CH₃COOCH₃(aq) + H₂O(l)

• CaCO₃(s) → CaO(s) + CO₂(g)

A catalyst is added to a system at equilibrium. If the temperature remains constant, the activation energy of the forward reaction:

• decreases

• increases

• remains the same

Adding a catalyst to a chemical reaction changes the rate of reaction by causing:

• a decrease in the activation energy

• an increase in the activation energy

• a decrease in the heat of reaction

• an increase in the heat of reaction

Which change would most likely increase the rate of a chemical reaction?

• decreasing a reactant's concentration

• decreasing a reactant's surface area

• cooling the reaction mixture

• adding a catalyst to the reaction mixture

Given the reaction: A + B → C + D, the reaction will most likely occur at the greatest rate if A and B represent:

• nonpolar molecular compounds in the solid phase

• ionic compounds in the solid phase

• solutions of nonpolar molecular compounds

• solutions of ionic compounds

1-cubic-centimeter cube of sodium reacts more rapidly in water at 25°C than does a 1-cubic-centimeter cube of calcium at 25°C. This difference in rate of reaction is most closely associated with the different:

• surface area of the metal cubes

• nature of the metals

• density of the metals

• concentration of the metals

If a catalyst is added to a system at equilibrium and the temperature and pressure remain constant, there will be no effect on the:

• rate of the forward reaction

• rate of the reverse reaction

• activation energy of the reaction

• heat of reaction