• Calculating Rate

• Rate of reaction is the change in the amount of reactants or products over time
• Rate = Amount of Reactants used or Amount of product formed
Time

Measuring Rate

• To find the rate of reaction several tests must be carried out throughout the experiment using either:
• Time taken for precipitate to form

When the product formed causes a precipitate to form as a cloud in a solution

Method: 1) stand a conical flask over a white tile with a cross on it

2) add a fixed amount of reactants to the conical flask and start a stopwatch

3) observe the solution to until you are unable to see the cross

Change in Mass:

When the product formed is a gas, then the rate of reaction can be measured using the change in mass

Method: 1) place a conical flask on a weighing scales

2) Reactants are mixed together in a conical flask and a stopwatch is started

3) at regular time intervals, read the new mass of the reactants

Gas Volume

If a gas is given off in a reaction, then the rate of reaction can be calculated based on the volume of gas collected in a gas syringe and recording the volume over different time periods

Method: 1) Reactants are mixed together in a conical flask and a gas syringe is attached and sealed onto it

2) start a stopwatch as soon as the reaction starts

3) at regular time intervals, read how much volume of gas has been produced