Find the mass of carbon dioxide that forms during decomposition 180 grams of calcium carbonate containing 4% impurities.

1. Let’s write the reaction equation:

CaCO3 = CaO + CO2.

2. Find the mass of calcium carbonate, and then its amount:

ω (CaCO3) = 100% – ω (impurities) = 100% – 4% = 96%.

m (CaCO3) = (m (mixture) * ω (CaCO3)) / 100% = (180 g * 96%) / 100% = 172.8 g.

n (CaCO3) = m (CaCO3) / M (CaCO3) = 172.8 g / 100 g / mol = 1.728 mol.

3. Using the reaction equation, we find the amount of carbon dioxide, and then its mass:

n (CO2) = n (CaCO3) = 1.728 mol.

m (CO2) = n (CO2) * M (CO2) = 1.728 mol * 44 g / mol = 76 g.

Answer: m (CO2) = 76 g.