Hint: Heat is a form of energy that is transferred from one body to another body due to the difference in the temperature. Thus if the two bodies of two different temperatures are brought together, heat flows from the hotter body to the colder body.
Complete step by step answer: At higher temperatures, the chemical reactions occur more rapidly. As the average kinetic energy of the particle increases, the particles will move faster and collide with each other per unit time more frequently and thus possess greater energy whenever they collide.
The average kinetic energy of the molecules increases, whenever the reactants are heated which indicates that more molecules are moving fastly and hitting each other with more energy. Thus when more molecules hit each other to react, the rate of the reaction also increases.
The chemical reactions involve the breaking and the formation of chemical bonds. It takes the energy to break the chemical bond and then the energy is released. Thus if more energy is released than consumed, the chemical reactions evolve heat.
Whenever the heat energy is increased, temperature also increases which in turn increases the average kinetic energy of the molecules. It means there are more collisions and the higher frequency of successful collisions between these reactants during the reaction, up the chemical reaction.
Note: 1. Heat is necessary in order to initiate the chemical reaction and the chemical reactions are used to produce the energy. 2. The examples of chemical changes are cooking an egg, frying an egg etc, as these results in the hot formation of the new particles.