Calculate the mass fraction of impurities in a limestone sample, if it is known that upon decomposition

| April 19, 2021 | education

Calculate the mass fraction of impurities in a limestone sample, if it is known that upon decomposition of 160 grams of this sample, an oxide weighing 60 grams was obtained.

1. Let’s compose the equation of the chemical reaction:

CaCO3 = CaO + CO2.

2. Find the chemical amount of calcium oxide:

n (CaO) = m (CaO) / M (CaO) = 60 g / 56 g / mol = 1.07 mol.

3. According to the reaction equation, we find the chemical amount, and then the mass of calcium carbonate:

n (CaCO3) = n (CaO) = 1.07 mol.

m (CaCO3) = n (CaCO3) * M (CaCO3) = 1.07 mol * 100 g / mol = 107.14 g.

4. Find the mass fraction of impurities in the mixture:

ω (CaCO3) = m (CaCO3) / m (mixture) * 100% = 107.14 g / 160 g * 100% = 66.96%.

ω (impurities) = 100% – ω (CaCO3) = 100% – 66.96% = 33.04%.

Answer: ω (impurities) = 33.04%.



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