A chemical reaction is a change that produces one or more new substances from some starting materials. Usually the starting materials are two different substances but not always. These are some examples of chemical reactions:
a candle burning
iron rusting
fireworks and explosions
frying an egg
respiration in living cells
photosynthesis in green plants
Rusting is a slow chemical reaction
In each example, we have starting substances that react together to make new substances. The starting substances are called reactants and the new substances made are called products.
Let's look at the example of the candle burning. When substances burn, they react with oxygen in the air. So, the reactants in this example are the candle wax and the oxygen. When the candle wax and oxygen react together, they make two products. These are carbon dioxide and water vapour.
Candle wax and oxygen react together quickly to make carbon dioxide and water vapour
