C2 Topic 5

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A student carried out four experiments W, X, Y and Z. In each experiment she added the same mass of calcium carbonate to the same volume of hydrochloric acid. The reaction produced a gas. Every minute, for five minutes, she measured the volume of gas that had been given off. The conditions in all experiments were kept the same, except that different sized pieces of calcium carbonate were used. The following is a table of the student's results


  • A. Reaction W has the fastest rate in the first minute.
  • B. Reaction X has the fastest rate in the first minute.
  • C. Reaction Y has the fastest rate in the first minute.
  • D. Reaction Z has the fastest rate in the first minute.

Which reaction above did not finish within five minutes ?

  • A. W
  • B. W
  • C. Y
  • D. Z

To increase the rate of reaction in experiment X above, the student should

  • A. Decrease the concentration of the acid
  • B. Use bigger pieces of calcium carbonate
  • C. Increase the temperature of the acid
  • D. Use a smaller volume of the same acid

A catalyst can be added to a reaction mixture to change the rate of the reaction. Which row of the table shows the effect that a catalyst has on the rate of a reaction and how the mass of the catalyst after the reaction compares with the mass of catalyst added

  • A. Rate of reaction increases. The mass of catalyst is unchanged
  • B. Rate of reaction increases. The mass of catalyst decreases
  • C. Rate of reaction decreases. The mass of catalyst is unchanged
  • D. Rate of reaction decreases. The mass of catalyst decreases