What mass of lactic acid is formed as a result of lactic acid fermentation of glucose weighing 90 g?

What mass of lactic acid is formed as a result of lactic acid fermentation of glucose weighing 90 g? The acid yield is 80%.

1. Lactic acid fermentation of glucose describes the reaction equation:

C6H12O6 → 2C3H6O3;

2. Let’s calculate the chemical amount of glucose:

n (C6H12O6) = m (C6H12O6): M (C6H12O6);

M (C6H12O6) = 6 * 12 + 12 + 6 * 16 = 180 g / mol;

n (C6H12O6) = 90: 180 = 0.5 mol;

3. Determine the theoretical amount of lactic acid:

ntheor (C3H6O3) = n (C6H12O6) * 2 = 0.5 * 2 = 1 mol;

4. Let’s establish the practical amount of the formed acid:

npr (C3H6O3) = ntheor (C3H6O3) * ν = 1 * 0.8 = 0.8 mol;

5. Let’s calculate the mass of lactic acid:

m (C3H6O3) = npr (C3H6O3) * M (C3H6O3);

M (C3H6O3) = 3 * 12 + 6 * 1 + 3 * 16 = 90 g / mol;

m (C3H6O3) = 0.8 * 90 = 72 g.

Answer: 72 g.