Lesson 1 What is a rate Chemistry Key

Lesson 1 - What is a rate? Chemistry- Key Stage 3 Energetics Sally Charlton 1

Definitions of terms What do I mean by ‘rate of reaction’? Rate of reaction is the _______ of the… What do I mean by ‘activation energy’? Activation energy is the _______ amount of energy the ____ need. . . 2

Suggest how you could measure the rate of each reaction Remember to use one of the following changes: • How long a reaction takes to complete. • How quickly a reactant is used up. • How quickly a product is made. • The number of bubbles/volume of gas produced per minute. 3

Photosynthesis 4

Calcium carbonate and acid 5

Sodium Thiosulphate and acid 6

Measuring the rate of reaction Identify the variables This practical shows the reaction between magnesium and hydrochloric acid, by measuring the volume of gas (cm 3) produced every 20 seconds up to 2 minutes. 7

Answers 8

Definitions of terms What do I mean by ‘rate of reaction’? Rate of reaction is the speed of the chemical reaction. What do I mean by ‘activation energy’? Activation energy is the minimum amount of energy the particles need to collide and react together. 9

Photosynthesis • Measure the volume of oxygen given off per minute, hour etc. • Count the number of bubbles per minute 10

Calcium carbonate and acid • Time taken for marble chips to disappear • Time until solution stops bubbling • Measure the change in mass per minute 11

Sodium Thiosulphate and acid The time taken for the X to disappear. 12

Review your answers Independent variable: Time (s) Dependent variable: Volume of gas (cm 3) Control variable: concentration of acid, type of acid, volume of acid, type of metal, mass of magnesium. 13