A chemical change is one in which a new substance is formed during the process of this change and it's not reversible.
A metal railing rusting in damp weather is an example of a chemical change because a new substance called Rust (Fe2O3) you is formed when iron reacts chemically with air.
<span>Chemical Energy is energy stored in the bonds of chemical compounds (atoms and molecules). It is released in a chemical reaction, often producing heat as a by-product (exothermic reaction). Batteries, biomass, petroleum, natural gas, and coal are examples of stored chemical energy.
