In both chemical and physical changes, energy is either absorbed or emitted. For example, when ice changes to water energy is absorbed to loosen the inter-molecular bonds while during the formation of water from steam energy is emitted.
In physical changes no bonds are broken or new products formed formed as the end product has the same composition as the reactants while in a chemical change new products are formed as there is bond breaking and and formation of new bonds hence new products.
Physical changes are easily reversible while chemical changes are not reversible.