CONTENTS

Background Science......................................................................................................................... Page 3, 4

Introduction/Aim……………………………………………………………………………………………... Page 5
What is a preliminary test? ............................................................................................................... Page 5

Prediction……………………………………………………………………………………………..…………. Page 5

Preliminary table……………………………………………………………………………………………… Page 6

Preliminary Method………………………………………………………………………..…………….. Page 6, 7

Preliminary apparatus ……………………………………………………………………………..…… Page 5, 6

Preliminary safety …………………………………………………………………………………………… Page 7

Apparatus……………………………………………………………………………………………………. Page 7, 8

Methodology …………………………………………………………………………………………………… Page 7

Main Experiment Results Table………………………………………………………………………. Page 11

How to make it a fair test………………………………………………………………………… Page 11, 12

Variables………………………………………………………………………………………………..…. Page 13, 14

Analysis of graphs…………………………………………………………………………………….....…. Page 14

Anomalous results and experimental improvements………………………..……………… Page 15

Conclusion……………………………………………………………………………………..…………. Page 15, 16

Evaluation………………………………………………………………………………….... Page 17, 18, 19, 20

Bibliography…………………………………………………………………………………...……………… Page 21

BACKGROUND SCIENCE

The 5 Factors that affect the rate of a chemical reaction:

• Concentration

• Temperature

• Gas pressure

• Catalyst

• Surface area of particles (1)

Rates of reaction:

How quickly a reaction happens is called the rate of reaction. Chemical reactions take place when two or more chemicals react with one another by colliding with each other. The increase in temperature increases the amount of collisions between particles, this fastens the reaction. If a reaction has a low rate that means the molecules combine at a slower speed than a reaction with a high rate. Particles need a minimum amount of kinetic movement if they are going to react when they collide. This is known as Activation energy. Different reactions happen at different rates. Reactions that occur slowly have a lower rate of reaction.

THE COLLISION THEORY

In a reaction particles move around each other causing millions of collisions every second. The collision theory is the idea that for a reaction to happen particles must collide with the correct orientation and with enough energy to produce a reaction. Collisions that result in a reaction are called ‘successful’ (fruitful) collisions. Fast reactions are due to an increase of successful collisions; slow reactions are due to fewer successful collisions. Reactions that happen quickly have a high rate of reaction (e.g. explosions).

Concentration:

The concentration of a solution is how strong the solution is. A stronger acid contains more acid particles and less water particles than a weaker acid. Increasing the concentration of a solution leads to more collisions (greater frequency of collisions) so the rate of the reaction goes up. With a more concentrated acid, the number of acid particles is greater, so the number of collisions is greater and the rate of the reaction is higher (faster.) Changing the concentration of the acid does not change how quickly the particles are moving (i.e. it doesn't increase the amount of energy they have.)

Temperature:
When we increase the temperature at which a reaction is taking place, the particles move more quickly. At a lower temperature, the number of collisions is lower because the particles are moving more slowly. Also when a collision occurs, there is less chance of a reaction taking place because the movement energy in the particles is less. At a higher temperature, the number of collisions is greater because the particles are moving more quickly. When a collision occurs, there is more chance of a reaction taking place