When calcining a limestone weighing 54 g, 22 g of carbon dioxide were released.

When calcining a limestone weighing 54 g, 22 g of carbon dioxide were released. Calculate the mass fraction of calcium carbonate in limestone.

The limestone roasting reaction is described by the following equation:

CaCO3 = CaO + CO2 ↑;

When decomposing 1 mol of limestone, 1 mol of calcium oxide and 1 mol of carbon monoxide is obtained.

Find the molar amount of calcium carbonate. For this purpose, we divide its weight by its molar weight.

M CaCO3 = 40 + 12 + 16 x 3 = 100 grams / mol; N CaCO3 = 54/100 = 0.54 mol;

Let us determine the mass of 0.54 mol of carbon dioxide.

To do this, multiply the amount of substance by the weight of 1 mole of gas.

M CO2 = 12 + 16 x 2 = 44 grams / mol;

m CO2 = 0.54 x 44 = 23.76 grams;

The mass fraction of carbonate in limestone is equal to the reaction yield: 22.00 / 23.76 = 0.926 = 92.6%;