The equation, with states
This is the equation you met in grade 10. Everything in it is the same except one addition — and that addition is what makes it a grade-11 equation.
Photosynthesis
carbon dioxide + water → glucose + oxygen
6CO2(g) + 6H2O(l) → C6H12O6(s) + 6O2(g)
Above the arrow: light. Below the arrow: chlorophyll.
The state symbols
The letter in brackets after each formula says what physical state that substance is in during the reaction:
- (g) — a gas. Carbon dioxide going in, oxygen coming out.
- (l) — a liquid. The water taken up from the soil.
- (s) — a solid. The glucose, which is why it can be stored.
Read the states and the whole chapter is in them
Two gases means two things crossing a stomatal pore. A liquid means a plumbing problem, solved by the xylem. A solid means something that can be piled up and kept, which is the starch in the leaf. The three letters in brackets are a summary of the three previous pages.
Beyond the syllabus — which colours are used
In photosynthesis, green plants absorb the red and blue parts of sunlight. The green is largely reflected rather than absorbed — which is exactly why a leaf looks green to you. The colour of a plant is the colour it is not using.