Section 9 - Rates of Reactions

Question 1

What are the four ways of measuring the rate of a reaction?

Answer 1

1) You can measure the change in mass that occurs during a reaction where gas is released as one of the products.
2) You can follow the colour change of a reaction. This includes precipitation reactions, where the solution turns cloudy as more of the product is made.
3) You can measure changes in temperature or pH that occur during the reaction.
4) You can measure the volume of gas produced during a reaction.

Question 2

Describe how to measure the rate of reaction between hydrochloric acid and magnesium metal

Answer 2

• Use a gas syringe to collect the hydrogen gas that is given off during the reaction.
• Use a stopwatch to time the reaction.
• At timed intervals, say every 30 seconds, record how much hydrogen gas has been produced.
• Plot a graph where you can tell how fast the rate is depending on the steepness of the curve.