How much air is required to burn 10 kg coal containing 40% of impurities. Mass fraction of oxygen in the air is 21%.

The reaction of carbon with oxygen takes place according to the following chemical reaction equation:

C + O2 = CO2;

To oxidize 1 mole of carbon, 1 mole of oxygen is required.

The mass of pure carbon will be 10,000 x 0.4 = 4,000 grams.

Let’s find the amount of carbon.

M C = 12 grams / mol;

N C = 4000/12 = 333.3 mol;

To burn this amount of carbon, 333.4 moles of oxygen are required.

Let’s find its volume.

One mole of gas fills a volume of 22.4 liters under normal conditions.

The oxygen volume will be equal to:

V О2 = 333.3 x 22.4 = 7 466 liters;

The volume concentration of oxygen in the air is 21%.

The required air volume is:

V air = 7 466 / 0.21 = 35 552 liters = 35.552 m3;