What mass of calcium oxide is obtained by heating 50 g of calcium carbonate? (CaCO3 = 100, CaO = 56)
Answer and explanation
Correct answer: B. 28 g
- Step 1: CaCO3 gives CaO + CO2, one mole to one mole. Step 2. Moles of CaCO3 = 50 / 100 = 0.5 mol, so 0.5 mol of CaO is formed. Step 3. Mass = 0.5 x 56 = 28 g. Answer: 28 g. Why not the others: 50 g: That assumes no mass is lost, but carbon dioxide escapes. 22 g: That is the mass of carbon dioxide released. 56 g: That is the mass of a whole mole of calcium oxide, but only half a mole forms.
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