Chemical reaction involves the breaking of bonds in the reactants and formation of bonds in the products. ... If a reaction is exothermic, more energy is released when the bonds of the products are formed than it takes to break the bonds of the reactants. This is the reason for temperature change during a reaction.
Explanation:
Here are just a few everyday demonstrations that temperature changes the rate of chemical reaction: Cookies bake faster at higher temperatures. Bread dough rises more quickly in a warm place than in a cool one.
A physical change is one in which there is no change in chemical composition of a substance. while a process in which there is change in chemical composition it is called a chemical change.