... taken for the reaction to take place. Watching the cross disappear as precipitation occurs and sulphur is formed as a solid will be the method used to realise the rate. My controlled variables will be the temperature, the concentration of hydrochloric acid, the amount of sodium thiosulphate and the amount of hydrochloric acid. I will try and control these as far as possible, and be as accurate as I can when measuring out the chemicals. I will not be using a catalyst. Prediction. I predict that the higher the concentration of sodium thiosulphate, the quicker it will react with the hydrochloric acid. This prediction is explained by the theory below: - When two chemicals react, their molecules have to collide with each other with sufficient energy for the reaction to take place. This is collision theory. The two molecules will only react if they have enough energy. This is known as activation energy. Increasing the ...

See this essay or coursework document in full right now