As a result of the reaction of the silver mirror, silver was obtained with a chemical amount of 0.025 mol.

As a result of the reaction of the silver mirror, silver was obtained with a chemical amount of 0.025 mol. Calculate the mass of the methanal that has reacted.

1. Let us draw up a scheme for the oxidation reaction of methanal with an ammonia solution of silver:

HCOH + Ag2O → HCOOH + 2Ag ↓.

2. It can be seen from the reaction scheme that when one mole of methanal reacts with silver oxide, two moles of silver are released, then the amount of methanal is:

n (HCOH) = n (Ag): 2 = 0.025: 2 = 0.0125 mol.

3. Calculate the mass of methanal:

m (HCOH) = n (HCOH) * M (HCOH);

M (HCOH) = 1 + 12 + 16 + 1 = 30 g / mol;

m (HCOH) = 0.0125 * 30 = 0.375 g.

Answer: 0.375 g.