ethanol production

Question 1

how do you make ethanol from crude oil

Answer 1

ethene is produced when curde oil fractions are cracked

to make ethanol you hydrate ethene with phosphoric acid as a catalyst which produces ethanol

Question 2

formula of ethanol

Answer 2

C2H5OH

Question 3

how do you make ethanol from crude oil

Answer 3

ethene is produced when crude oil fractions are cracked

to make ethanol you hydrate ethene with phosphoric acid as a catalyst which produces ethanol

Question 4

Give 2 reasons why making ethanol by fermentation better than making ethanol from crude oil

Answer 4

• it is cheaper than hydration as it can be carried out at a much lower temperature
• the source produced is a renewable source of ethene

Question 5

give one limitation of making ethanol by fermentation

Answer 5

• it is a batch process so it is slower with a lower percentage yield

Question 6

write the symbol equation for the anaerobic respiration of glucose

Answer 6

C6H12O6 (aq) —> 2C2H4OH (aq) + 2CO2 (g)

Question 7

what are the conditions for anaerobic respiration

Answer 7

• temperature of 35C
• air is kept out of fermentation vessel to prevent oxidation of ethanol to form ethanoic acid

Question 8

why does fermentation stop when the solution contains 15% ethanol

Answer 8

the enzymes are unable to function so fermentation stops

ethanol may be distilled from this mixture by fractional distillation

Question 9

compare the methods of making ethanol by fermentation to making ethanol from crude oil

in terms of
rate of reaction
type of process
purity

Answer 9

making ethanol from crude oil
rate of reaction - fast
type of process - continuous
purity - essentially pure

making ethanol by fermentation
rate of reaction - slow
type of process - batch
purity - aqueous solution of ethanol is produced