Photosynthesis is the reaction in which plants and algae make glucose. The reactants are carbon dioxide and water. The products are glucose and oxygen. It happens in the chloroplasts, which contain the green pigment chlorophyll that absorbs light.
Word equation: carbon dioxide + water → glucose + oxygen, in light. Symbol equation: 6CO2 + 6H2O → C6H12O6 + 6O2.
It is a two-stage process. In the first stage, chlorophyll absorbs light energy, which is used to split water into hydrogen and oxygen. The oxygen is a waste product and leaves the leaf. In the second stage, the hydrogen is combined with carbon dioxide to make glucose. The carbon dioxide enters the leaf from the air, and the water is taken up by the roots.
