50g of limestone contains calcium carbonate and various impurities, treated with nitric acid.

50g of limestone contains calcium carbonate and various impurities, treated with nitric acid. the gas obtained as a result of the reaction with a volume of 10 liters. calculate the mass fraction of impurities in the limestone.

When calcium carbonate interacts with nitric acid, calcium nitrate, water and gaseous carbon dioxide are synthesized. The reaction proceeds according to the following chemical equation:

CaCO3 + 2HNO3 = Ca (NO3) 2 + CO2 ↑ + H2O;

Find the molar amount of a substance contained in 10 liters of carbon dioxide. For this purpose, we divide its volume by the volume of 1 mole of gas (which is 22.4 liters).

N CO2 = 10 / 22.4 = 0.446 mol;

To obtain this amount of carbon dioxide, an equivalent amount of calcium carbonate must be decomposed.

Let’s determine its weight.

To do this, we multiply the amount of the substance by its molar weight.

M CaCO3 = 40 + 12 + 16 x 3 = 100 grams / mol; m CaCO3 = 0.446 x 100 = 44.6 grams;

The mass of impurities in limestone will be 50 – 44.6 = 5.4 grams;

The mass fraction of impurities will be 5.4 / 50 = 0.108 = 10.8%;