Effect of Increasing the Temperature on the Rate of Reaction
In order for a reaction to occur, the reactant molecules have to collide with each other, and they need to collide with enough energy (greater than the activation energy). At any given temperature, some molecules are moving very slowly, some are more moving fast, and some are moving very fast. Reactant molecules that are moving too slowly do not react when they collide; they just bounce off of each other without reacting.
Increasing the temperature increases the rate of a reaction because, as the temperature increases, the reactant molecules move faster and are more likely to collide with each other. More collisions means that the rate of reaction will increase.
Also, at higher temperatures, since the molecules are moving faster, they collide with greater energy. That means more molecules will collide with an energy that is greater than the activation energy so that more of the collisions will result in a reaction.