A sample of ethanol has a molecular formula of C₂H₆O. What is the percentage by mass of carbon in ethanol? (Relative atomic masses: C = 12, H = 1, O = 16)

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Question

A sample of ethanol has a molecular formula of C₂H₆O. What is the percentage by mass of carbon in ethanol? (Relative atomic masses: C = 12, H = 1, O = 16)

Accepted Answer

52.2% — Award 1 mark for 52.2%. Working: Mr of C₂H₆O = (2 × 12) + (6 × 1) + 16 = 46. Mass of carbon = 2 × 12 = 24. Percentage = (24/46) × 100 = 52.2%. A is incorrect (calculation error). C is incorrect (this would be percentage of oxygen). D is incorrect (calculation error).

Answer

52.2%

Answer

13.0%

Answer

34.8%

Answer

26.1%

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