Measuring rates of reaction

The rate of reaction can be found by measuring the amount of product formed, or the amount of product lost, over a certain period of time.

The massof a solid product is measured in grams, while the volume of a gaseous product is measured in cm3.

Rate is most often calculated using the equation: rate =  \frac {1}{time} where the time is the time for the reaction to reach a certain point or the time for the reaction to be completed. The units of rate calculated in this way are s-1.

Measuring the rate when a gas is produced

The apparatus you use depends on the nature of the product being measured.

  • the mass of a substance - solid, liquid or gas - is measured with a balance.
  • the volume of a gas is usually measured with a gas syringe (or sometimes with an upside-down measuring cylinder).
A sealed conical flask connected to a gas syringe. The flask contains a reaction mixture that is giving off bubbles of gas.