Calculating Rate of Reaction

• It's often useful to calculate the rate of reaction after an experiment
• Rate is a measure of how much something changes over time
• For the experiment above, you can calculate the rate of reaction using the formula: Rate = 1000 / time
• E.g. At pH 6, the time takenfor amylase to break down all o the starch in a solution was 90 s. So the rate of the raction = 1000 / 90 = 11 s−1 (2 s.f.)
• Units are in s−1 since the rate is given per unit time
• If an experiment measures how much something changes over time, you calculate the rate of reaction by dividing the amount that it has changed by the time taken
• E.g. The enzyme catalase catalyses the breakdown of hydrogen peroxide into water and oxygen. During an investigation into the activity of catalase, 24 cm^3 of oxygen was released in 50 s. Calculate the rate of reaction. Write your answer in cm^3/s?

  Amount of product formed = change = 24 cm^3

  Rate of reaction = change / time = 24 / 50 = 0.48 cm^3/s