AP Biology question on writing equations

Question

Write an equation that uses the products of photosynthesis as reactants and uses the reactants as products. Add energy as another product. 

Answer 1

Well, the products of photosynthesis are glucose and oxygen gas, while the reactants are water, carbon dioxide, and, apparently, energy. So using the products as reactants, and the reactants as products, we get:

 

C₆H₁₂O₆ + 6 O₂ --> 6 CO₂ + 6 H₂O + [energy]

 

after balancing the equation.