This is a typical GCSE chemistry question relating to collision theory. Collision theory states that for a reaction to occur, the reactant particles must collide at a sufficient level of energy. To answer this question, we question how increasing the temperature affects how the reactant particles collide: -When temperature is higher, particles move faster -> There are more collisions per unit of time -> There are more sucessful collisions per unit time -When temperature is higher, particles contain more kinetic energy -> A greater proportion of collisions occur at sufficient energy to trigger a reaction per unit of time -Both factors work together to cause the rate of reaction to increase Exam Technique: -Display answer in a logical format to make it easier for examiner to mark -Per unit of time is highlighted due to its importance. Simply stating that there are more collisions is not sufficient to gain a mark, you must state that there are more collisions in a specified amount of time.