Gasoline burning is an example of a chemical change, because this process produces water vapor and carbon dioxide. For something to be categorized as a chemical change, it must form new chemical substances. It also entails making and breaking molecular bonds. Another example is iron rusting, which forms iron oxide.
Unlike in a physical change, no new substance is formed. There's likewise no change in the internal structure of a substance's molecules, but only a rearrangement. A popular example of a physical change is boiling water, where liquid water changes to vapor, but the same molecule of H2O remains . Another example is whipping egg whites. Air is simply incorporated into the egg white's structure, but no new substance is formed.