When melting 18 kilograms of limestone with quartz sand, 20 kg of calcium silicate were formed

When melting 18 kilograms of limestone with quartz sand, 20 kg of calcium silicate were formed, calculate the mass fraction of calcium carbonate in the limestone.

The reaction of interaction of limestone with silicon oxide is described by the following equation:

CaCO3 + SiO2 = CaSiO3 + CO2 ↑;

When 1 mol of limestone and 1 mol of silicon dioxide interact, 1 mol of calcium silicate is synthesized.

Let’s calculate the chemical amount of the formed calcium silicate. For this purpose, we divide its weight by its molar mass.

M CaSiO3 = 40 + 28 + 16 x 3 = 116 grams / mol; N CaSiO3 = 20,000 / 116 = 172.4 mol;

We calculate the weight of 172.4 mol of calcium carbonate.

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

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

m CaCO3 = 172.4 x 100 = 17 240 grams;

Mass fraction of calcium carbonate in limestone is 17 240/20 000 = 0.862 = 86.2%;