Making ethanol by fermentation
3 marks · NormalIn a fermentation process, 180 g of glucose is completely converted to ethanol and carbon dioxide.
Calculate the mass of ethanol produced.
The equation for fermentation is:
M_r values: glucose (C6H12O6) = 180, ethanol (C2H5OH) = 46
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92 g (±1)
Common mistakes: Using wrong ratio of ethanol to glucose; Calculating moles wrongly
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Marking points
M1 · 1 mark · Calculates moles of glucose: 180/180 = 1 mol.
M2 · 1 mark · Uses correct mole ratio: 1 mol glucose makes 2 mol ethanol.
A1 · 1 mark · Calculates mass of ethanol: 2 x 46 = 92 g. (follow-through)
Worked solution
Fermentation gives 2 mol ethanol per 1 mol glucose.