Question :
1. The rate of a reaction can be increased by : 1335517
1. The rate of a reaction can be increased by all of the following except:
A)increasing the temperature.
B)increasing the concentration of the reactants.
C)increasing the surface area of the reactants.
D)adding a catalyst.
E)increasing the volume of the reaction vessel.
2. Which of the following will not increase the rate of a reaction?
A)decreasing the temperature
B)decreasing the concentration of the reactants
C)decreasing the surface area of the reactants
D)removing a catalyst
E)all of these choices are correct
3. Factors that influence reaction rates include all of the following except the
A)magnitude of the equilibrium constant.D)size of solid reactant particles.
B)reaction temperature.E)concentration of reactants.
C)presence of a catalyst.
4. According to collision theory, the increase in the rate constant with increasing temperature is due mostly to the fact that
A)the activation energy decreases with increasing temperature.
B)the fraction of the collisions having sufficient energy to react increases with increasing temperature.
C)the pressure of the reactants increases with increasing temperature.
D)the heat change for most reactions is negative.
E)the fraction of the collisions that have the proper orientation for reaction increases with increasing temperature.
5. Which of the images shows the molecules in a proper orientation for an effective collision for the reaction:
2HI(g) ? H2(g) + I2(g)
A) I only B) II only C) III only D) I and II E) II and III
6. Which of the following changes will increase the average kinetic energy of the reactants?
A)increasing the surface area of the reactants
B)increasing the concentration of the reactants
C)adding a catalyst
D)increasing the temperature
E)none of these choices
7. Which of the following changes will increase the fraction of collisions that are effective collisions?
A)increasing the temperature
B)increasing the concentration of the reactants
C)decreasing the concentration of the reactants
D)increasing the surface area of the reactants
E)all of these choices are correct
8. The kinetics of a reaction is studied at 25?C and at 50?C. Which of the following statements is correct?
A)The rate of the reaction at 50?C will be lower than the rate at 25?C, since the molecules will be moving too fast to collide effectively.
B)The rate of the reaction at 50?C will be twice that of the rate at 25?C, since the temperature has doubled.
C)The rate of the reaction at 50?C will be greater than the rate at 25?C, since the activation energy will be lower at the higher temperature.
D)The rate of the reaction at 50?C will be greater than the rate at 25?C, since a greater fraction of the molecules will possess sufficient energy to react at the higher temperature.
E)None of these statements is correct.
9. Which of the following statements regarding catalysts is incorrect?
A)A catalyst increases the rate of a reaction by giving the reaction an alternate pathway with a lower activation energy.
B)Catalysts need not be present in large amounts because they are regenerated during the reaction.
C)Enzymes act as catalysts in our bodies.
D)In a chemical reaction, the catalyst is shown on the reactant side of the equation.
E)The shape of an active site on an enzyme is unique, allowing it to react with only one substrate.
10. Which of the following statements regarding catalysts is incorrect?
A)A catalyst increases the rate of a reaction by giving the reaction an alternate pathway with lower activation energy.
B)A catalyst is formed temporarily in an early step of a reaction.
C)Most enzymes are large protein molecules.
D)In a chemical equation the catalyst is shown above the reaction arrow of the equation.
E)The shape of an active site on an enzyme is unique, allowing it to react with only one substrate.
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