Comparing the two methods of producing ethanol
5 marks · HardA chemical company is choosing between fermentation and hydration of ethene to manufacture ethanol.
State one raw material used in each method.
Explain one environmental advantage of using fermentation rather than hydration to produce ethanol.
Describe one disadvantage of fermentation compared to hydration of ethene for industrial production of ethanol.
State one condition or feature of the hydration of ethene process that makes it more efficient industrially than fermentation.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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(a) — · must show Fermentation: glucose, sugar cane, sugar beet, corn, starch-containing material, Hydration of ethene: ethene (from petroleum/oil)
(b) — · must show Fermentation uses renewable resources
(c) — · must show Fermentation is slower, batch process, less pure product, less efficient
(d) — · must show Continuous process, much faster or more efficient, produces purer ethanol
Common mistakes: Mixing up the resources or conditions for each method; Giving general statements about 'clean' or 'dirty' without chemical reasoning
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Correct raw material for fermentation (e.g. glucose, sugar cane, corn, etc.)
B2 (a) · 1 mark · Correct raw material for hydration (e.g. ethene from crude oil)
B3 (b) · 1 mark · Environmental advantage of fermentation (e.g. uses renewable resources)
B4 (c) · 1 mark · Any disadvantage of fermentation (e.g. takes longer, batch process, impure product)
B5 (d) · 1 mark · Correct efficiency-related feature of hydration (e.g. continuous, faster, produces pure ethanol)
Worked solution
a) Fermentation: glucose (sugar cane, sugar beet, corn, starch-containing materials). Hydration of ethene: ethene (from crude oil). b) Fermentation has the advantage of using renewable resources, making it better for the environment. c) Fermentation is a slow, batch process and produces impure ethanol needing further processing. d) The hydration of ethene process is continuous, much quicker, and produces purer ethanol.