what are two examples of a chemical reaction?
['The rusting of iron.', 'Combustion (burning) of wood.', 'The metabolism of food in the body.', 'Mixing an acid and a base, such as hydrochloric acid (HCl) and sodium hydroxide (NaOH)', 'Cooking an egg.', 'Digesting sugar with the amylase in saliva.', 'Mixing baking soda and vinegar to produce carbon dioxide gas.']