Making ethanol by fermentation

2 marks · Easy

In a fermentation reaction, 60 g of glucose are converted to ethanol and carbon dioxide. Calculate the maximum mass of ethanol that could be produced, using the equation:

(Relative formula masses: C6H12O6 = 180, C2H5OH = 46)

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15 g (±0.2)

Common mistakes: Incorrect ratio calculation

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Marking points

M1 · 1 mark · Moles or mass relationship for glucose and ethanol is correct. (follow-through)

A1 · 1 mark · Correct final answer for mass of ethanol (15 g). (follow-through)

Worked solution

Moles of glucose = 60 / 180 = 0.333 mol.

Each 1 mol glucose gives 2 mol ethanol:

Moles of ethanol = 0.333 × 2 = 0.666 mol.

Mass of ethanol = 0.666 × 46 = 15.3 g.

Final answer to 2 significant figures: 15 g.