Rates of Reaction :: GCSE Chemistry Coursework Investigation

The rate of reaction is a measure of how fast something happens. We can find the rate of reaction by measuring the change that happens in a set period of time. Introduction ------------ The rate of reaction is a measure of how fast something happens. We can find the rate of reaction by measuring the change that happens in a set period of time. Many factors can affect the rate of reaction; the concentration of the reactants is one of them. In the following experiments we will investigate how the concentration of the reactants affect the rate of reaction. To do this we will use the reaction between magnesium and hydrochloric acid. GRAPH I will measure the rate of reaction by timing how long the reaction takes. Aim- I am trying to find out how an increase/decrease in concentration of the acid affects the rate of reaction in magnesium strips. Prediction: I predict that as the concentration of hydrochloric acid increases the time taken for the magnesium to dissolve will decrease. I also think that when the concentration of the acid doubles the rate of reaction will also double. Collision Theory: The collision theory is how the rate of reaction increases when the concentration of hydrochloric acid increases. In the reaction firstly all of the particles in the reacting substances must collide. They must collide with a certain amount of energy called activation energy, this must be reached for the reaction to take place. If the particles do not reach this required amount of energy there will not be any successful collisions and therefore the reaction will not take place. If the particles do reach the required amount of energy a reaction will rake place and as the number of collisions increase the reaction speeds up. The more concentrated the reactants the larger the number of successful collisions between the particles. This explains why the largest rate of reaction is usually as soon as the reactants have been mixed together, this means they are both at their highest concentrations. High concentration Low concentration (18cm ³ HCL + 2cm ³ H ²O) (6cm ³ HCL + 14cm ³ H ²O) The temperature in this investigation will not affect the rate of reaction because throughout the investigation it will stay at room temperature. If the temperature was to change during the experiment it would effect the rate of reaction by speeding it up if the temperature increased because the particles move a lot faster and travel a larger