Comparing the two methods of producing ethanol
2 marks · EasyA chemical company can produce 50 tonnes of ethanol per week using either fermentation or hydration of ethene. The batch fermentation process is only 60% as efficient as the continuous hydration process.
Calculate how many tonnes of ethanol the company would produce per week if it switched from fermentation to hydration of ethene. Give your answer to the nearest tonne.
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83 tonnes (±1)
Also accept: 84 tonnes
Common mistakes: Not adjusting for increased efficiency (e.g. giving 50 tonnes as the answer).; Rounding errors.
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Marking points
M1 · 1 mark · Shows correct method to scale up by efficiency (e.g., divides 50 by 0.6 or multiplies by 100/60).
A1 · 1 mark · Arrives at correct final answer to the nearest tonne (83 or 84). (follow-through)
Worked solution
Hydration process produces more ethanol because it is more efficient.
Let x = ethanol from hydration (tonnes per week).
x = 50 / 0.6 = 83.333...
To the nearest tonne, the company would produce 83 tonnes of ethanol per week.