Solving Stoichiometry Problems

Question

The average human requires 120.0 g of glucose (C₆H₁₂O₆) per day. How many grams of CO₂ (in the photosynthesis reaction) are required in order to produce this amount of glucose? The photosynthesis reaction is: 6CO₂ + 2H₂O = C₆H₁₂O₆ + 6O₂

Answer 1

6CO₂ + 2H₂O = C₆H₁₂O₆ + 6O₂ ... balanced equation

molar mass C₆H₁₂O₆ = 180 g / mol

molar mass CO₂ = 44 g / mol

Use the mol ratio of CO2 : C₆H₁₂O₆ in the balanced equation and solve as follows:

120.0 g C₆H₁₂O₆ x 1 mol C₆H₁₂O₆ / 180 g x 6 mol CO₂ / mol C₆H₁₂O₆ x 40 g CO₂ / mol = 160 g CO₂