Calculate the mass of limestone containing 10% of impurities if, during its firing, calcium oxide weighing 112 g was obtained?

1. When calcining limestone, it decomposes. Let’s write the reaction equation:

CaCO3 = (t) = CaO + CO2;

1. Find the molecular weight of calcium oxide:

40 + 16 = 56 g / mol;

1. Let’s find the amount of substance in calcium oxide:

112/56 = 2 mol;

1. Let’s find the molecular weight of limestone:

40 + 12 + 16 * 3 = 100 g / mol;

1. The amount of substance in limestone is 2 mol, since the coefficients before calcium oxide and before limestone are the same. Let’s find the mass of limestone:

2 * 100 = 200 grams;

1. A mass of pure limestone has been found. Let’s find a mass of limestone with impurities:

200 / 0.9 = 222.22 grams;

Answer: the mass of limestone with impurities is 222.22 grams.