The diagram given below represents an experiment to prove the importance of a factor in photosynthesis (a leaf partly covered with black paper held by clips). Answer the questions that follow: The diagram given below represents an experiment to prove the importance of a factor in photosynthesis (a leaf partly covered with black paper held by clips). Answer the questions that follow:
Give a balanced chemical equation to represent the process of photosynthesis.
Topic: Equation for photosynthesis
Answer
6CO₂ + 12H₂O → C₆H₁₂O₆ + 6H₂O + 6O₂↑
(in the presence of SUNLIGHT and CHLOROPHYLL, written above and below the arrow)
SUNLIGHT and CHLOROPHYLL are CONDITIONS, not reactants — write them on the arrow, never on the left-hand side. Mark the ↑ after O₂ to show a gas is released.
WHY 12 WATER AND NOT 6: the simpler form balances arithmetically but is chemically misleading. Twelve molecules are split during PHOTOLYSIS and six are re-formed in the dark reaction, which is why water appears on BOTH sides.
It also makes an important point: the oxygen released comes from WATER, not from carbon dioxide — proved using radioactive oxygen-18 as a tracer.