Chemical reactions

Chemical reactions occur when substances interact to form new substances, involving the rearrangement of atoms. These changes can involve breaking old bonds and forming new ones, often releasing or absorbing energy. For example, burning wood transforms it into ash, smoke, heat, and light, while digestion breaks down food into usable nutrients. Reactions can happen slowly, like rust forming, or quickly, like fireworks exploding. They are fundamental to everything from biological processes to industrial production, governed by the principles of chemistry that determine how and when substances will react.