Summary:
- A chemical reaction is a process in which some substances change into different substances.
- Substances that start a chemical reaction are called reactants, and the substances produced are called products.
- There are four types of chemical reactions, including decomposition, replacement, and combustion.
- All chemical reactions involve energy.
- Energy is used to break bonds in reactants and released when new bonds form in products.
- Exothermic reactions release energy to the environment, often in the form of heat or light.
- When it comes to energy, the burning of wood is an exothermic reaction.