The rate of reaction between marble chips and hydrochloric acid can be increased by: a) increasing the concentration of the hydrochloric acid, b) increasing the temperature of the hydrochloric acid. Explain why in terms of the reacting particle model.(6)

(For a reaction to occur, reactant particles must collide and interact with each other in some way.The rate of a chemical reaction is proportional to the number of collisions between reactant molecules.)
Increasing the concentration of HCl increases the number of acid particles in the same volume of liquid. With more particles, there is an increased frequency of collisions. Therefore the rate of reaction increases with increased concentration.
Increasing the temperature of the acid increases the kinetic energy of each particle. When the acid particles move around faster, there is a greater chance of successful collisions between the acid and marble chips. Therefore rate of reaction increases because there are more collisions.