Catalyst and Catalysis

A catalyst can be described as a substance that:

• undergoes change to accelerate the rate of the reaction

• increases the kinetic energy of the reactants

• provides a path of lower activation energy for the reaction

• lowers the potential energy of the products with respect to the energy of the reactants

A catalyst will affect the rate of the forward reaction by changing the

• activation energy

• heat of reaction

• heat of formation

• potential energy of the products

Which of the following is most likely to increase the rate of a reaction?

• decreasing the temperature

• increasing the volume of the reaction vessel

• reducing the activation energy

• decreasing the concentration of the reactant in the reaction vessel

All of the following are true statements concerning catalysts except

• a catalyst will speed the rate-determining step

• a catalyst will be used up in a reaction

• a catalyst may induce steric strain in a molecule to make it react more readily

• a catalyst will lower the activation energy of a reaction

At equilibrium

• the forward reaction will continue

• a change in reaction conditions may shift the equilibrium

• the reverse reaction will not continue

• both (a) and (b)

Which statement is not correct regarding the function of a catalyst?

•   it affects the rate of a chemical reaction

• it lowers the energy of the product, causing the reaction to be more exothermic

• it changes the mechanism of a reaction

• it lowers the activation energy

Which of the following will lower the activation energy for a reaction?

• increasing the concentrations of reactants

• raising the temperature of the reaction

• adding a suitable catalyst

• there is no way to lower the activation energy of a reaction

The process in which reactants or products itself act as catalyst is called ------------

• catalysis

• positive catalysis

• negative catalysis

• auto-catalysis

Catalysts are -------

• specific

• non-specific

• always solids

• always liquid.

A catalyst

• changes the free energy change of a reaction

• is included in the balanced chemical equation for a reaction

• changes the mechanisms for a reaction

• slows down the rate of a reaction