Combustion<span>, </span><span>a </span>chemical reaction<span> between substances, usually including </span>oxygen<span> and usually accompanied by the generation of </span>heat<span> and </span>light<span> in the form of </span>flame<span>. </span>
<h3><u>Melting: the substance changes back from the solid to the liquid. Condensation: the substance changes from a gas to a liquid. Vaporization: the substance changes from a liquid to a gas. Sublimation: the substance changes directly from a solid to a gas without going through the liquid phase.</u></h3>
