In a reaction, 4.0 g of calcium carbonate (CaCO₃, Mr = 100) is heated to produce calcium oxide (CaO, Mr = 56). The actual mass of CaO collected is 1.96 g. What is the percentage yield?

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Question

In a reaction, 4.0 g of calcium carbonate (CaCO₃, Mr = 100) is heated to produce calcium oxide (CaO, Mr = 56). The actual mass of CaO collected is 1.96 g. What is the percentage yield?

Accepted Answer

A) 49% — Theoretical yield: (4.0 ÷ 100) × 56 = 2.24 g of CaO. Percentage yield = (1.96 ÷ 2.24) × 100 = 87.5%. Wait — re-checking: moles CaCO₃ = 4.0/100 = 0.04 mol; theoretical CaO = 0.04 × 56 = 2.24 g; % yield = (1.96/2.24) × 100 = 87.5%. The correct answer is B) 87.5%. Students commonly select A by dividing actual yield by Mr of reactant instead of theoretical yield.

Answer

A) 49%

Answer

B) 87.5%

Answer

C) 56%

Answer

D) 87%

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