Rate of Reaction Coursework Essay -- GCSE Chemistry Coursework Investi

Rates of Reaction A chemical reaction can only occur between particles when they collide (hit each other). Particles may be atoms, ions or molecules. There is a minimum amount of energy which colliding particles need in order to react with each other. If the colliding particles have less than this minimum energy then they just bounce off each other and no reaction occurs. This minimum energy is called the activation energy. The faster the particles are going, the more energy they have. Fast moving particles are more likely to react when they collide. You can make particles move more quickly by heating them up (raising the temperature). Changing the Rate of a Reaction. There are 5 ways to increase the rate of a chemical reaction. They are all understood in terms of collision theory. The rate of a chemical reaction may be increased by 1) Raising the temperature. 2) Increasing the concentration (in solution). 3) Increasing the pressure (in gases). 4) Increasing the surface area of a solid. 5) Use a catalyst. Measuring the Rate. The reaction between sodium thiosulphate solution and dilute hydrochloric acid. HCl + sodium thiosulphatearrowsodium chloride + sulphur dioxide + sulphur + water. HCl(aq) + Na2S2O3(aq) arrow NaCl(aq) + SO2(g) + S(s) + H2O(l) The solid sulphur (S(s)) formed in this reaction makes the colorless solution go cloudy. The reaction is usually carried out in a flask placed on a piece of white paper which has a ...