When coal with a mass of 187.5 g was burned, a CO2 volume of 336 liters was formed.

When coal with a mass of 187.5 g was burned, a CO2 volume of 336 liters was formed. Calculate the mass fraction of carbon in coal.

Let’s find the amount of substance carbon dioxide CO2.

n = V: Vn.

n = 336 L: 22.4 L / mol = 15 mol.

Let’s compose the reaction equation, find the quantitative ratios of substances.

C + O2 → CO2.

1 mole of coal accounts for 1 mole of carbon monoxide. The substances are in quantitative ratios of 1: 1. The amount of carbon monoxide and coal will be the same.

n (CO2) = n (C) = 15 mol.

Let’s find the mass of carbon by the formula:

m = n × M,

M (C) = 12 g / mol.

m = 12 g / mol × 15 mol = 180 g.

Find the mass of carbon,

187.5 g – 100%,

180 – x%,

x = (180 g × 100%): 187.5% = 96%.

Answer: 96%.