Worksheet: Catalysts

In this worksheet, we will practice explaining the effects of catalysts on the rate of reaction.

Q1:

Which one of the following statements about catalysts is false?

  • ACatalysts are unreactive.
  • BAfter catalysts react, they are regenerated.
  • CCatalysts increase the rate of a reaction.
  • DCatalysts do not appear in the overall reaction equation.

Q2:

Which of the following statements explains how catalysts increase the rate of reaction?

  • ACatalysts are consumed in the reaction, providing an alternate chemical pathway.
  • BCatalysts provide an alternate chemical pathway with higher activation energy.
  • CCatalysts provide alternate conditions with the same chemical pathway.
  • DCatalysts are consumed in the reaction, providing a greater surface area.
  • ECatalysts provide an alternate chemical pathway with a lower activation energy.

Q3:

Why is vanadium(V) oxide used as an industrial catalyst for the conversion of SO2 to SO3?

  • AThe metal oxide catalyst neutralizes the acidic SO3 gas.
  • BMore SO3 is produced every hour.
  • CThe vanadium(V) oxide is unchanged at the end of the conversion.
  • DThe catalyst increases the overall final yield of SO3.
  • EThe SO3 produced has a higher purity.

Q4:

In the following two diagrams, which two letters indicate reaction pathways that have been catalyzed?

  • AB and C
  • BB and D
  • CA and C
  • DA and D

Q5:

Which of the following statements about catalysts is untrue?

  • ACatalysts are often transition metals.
  • BCatalysts increase the overall frequency of collisions between particles.
  • CCatalysts are not used up in a reaction.
  • DCatalysts decrease the time it takes for a reaction to finish.
  • ECatalysts decrease the activation energy.

Q6:

Considering the diagram, which of the following statements is not true of a catalyzed reaction?

  • AThe catalyst provides an alternative reaction pathway.
  • BThe activation energy is smaller.
  • CThe overall energy change is the same.
  • DFewer particles have sufficient energy to react.
  • EThe catalyst is not consumed during the reaction.

Q7:

Experiment A relies upon a catalyst. If a greater quantity of the catalyst is used, what changes to the graph would be most likely?

  • AThe graph would be the same shape, and the final volume of gas collected would be lesser.
  • BThe graph would initially be less steep, and the final volume of gas collected would be the same.
  • CThe graph would be the same shape, and the final volume of gas collected would be greater.
  • DThe graph would initially be steeper, and the final volume of gas collected would be the same.
  • EThe graph would initially be less steep, and the final volume of gas collected would be lesser.

Q8:

Why do we often use small amounts of the catalyst compared to much greater amounts of the reactants when performing a reaction?

  • ACatalysts work better in smaller quantities.
  • BCatalysts should be used in low concentrations.
  • CCatalysts have very large surface areas.
  • DCatalysts are not consumed in reactions.
  • ECatalysts are hazardous chemicals.

Q9:

Catalysts are often used in the form of powder, mesh, small beads, or lattice. Which other factor that affects the rate of reaction is used here to enhance the effect of the catalyst?

Cross section of a car catalyst
  • AIncreased temperature
  • BIncreased pressure
  • CIncreased light intensity
  • DIncreased surface area
  • EIncreased concentration

Q10:

Fill in the blank: Specific protein-based catalysts in the human body are known as .

  • Aenzymes
  • Blipids
  • Cchloroplasts
  • Dcells
  • Enuclei

Q11:

Copper(II) oxide and chromium(III) oxide can both be used as catalysts for the decomposition of hydrogen peroxide, as shown: HO()HO()+O()2222aqlg In experiment A, copper(II) oxide is used, and in experiment B, chromium(III) oxide is used. The results are shown on the graph below. Which of the catalysts is the best and why?

  • AChromium(III) oxide is the better catalyst; the less steep slope indicates a faster rate of reaction.
  • BChromium(III) oxide is the better catalyst; the steeper slope indicates a faster rate of reaction.
  • CCopper(II) oxide is the better catalyst; the less steep slope indicates a faster rate of reaction.
  • DCopper(II) oxide is the better catalyst; the steeper slope indicates a faster rate of reaction.

Q12:

Which of the following is not a benefit of using catalysts in industrial processes?

  • AReactions can operate at lower temperatures.
  • BThe products are made more quickly.
  • CCatalysts do not need to be replaced often.
  • DReactions can operate at lower pressures.
  • ECatalysts are often rare transition metals.

Q13:

The shown reaction is the decomposition of hydrogen peroxide to form water and oxygen: 2HO()2HO()+O()2222aqlg Which of the following is the purpose of using a catalyst in this reaction?

  • ATo enable the reaction to take place
  • BTo produce more oxygen
  • CTo decrease the rate of reaction
  • DTo increase the rate of reaction
  • ETo make the reaction safer to perform

Q14:

Manganese dioxide is used as a catalyst in the decomposition of hydrogen peroxide to form water and oxygen: 2HO()2HO()+O()2222aqlg Which statement is not true when using MnO2 as a catalyst?

  • AThe catalyst remains unchanged at the end of the experiment.
  • BThe oxygen will be formed more quickly.
  • CAn alternative reaction pathway is provided by the catalyst.
  • DThe mass of MnO2 before and after the reaction will be the same.
  • EMore oxygen will be produced.

Q15:

Which of the following is shown by the red arrow in the sketch graph?

  • AThe heat loss
  • BThe exothermic change
  • CThe endothermic change
  • DThe activation energy
  • EThe enthalpy change

Q16:

What is the role of a catalyst in a reaction?

  • AIt shifts the equilibrium toward the products according to Le Chatelier’s law.
  • BIt donates electrons to break or form bonds as needed until it is entirely consumed.
  • CIt provides an alternate route with a lower activation energy for the reaction to proceed.
  • DIt forms bridging complexes that align the molecular orbitals of the reactants.
  • EAll of the above

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