Organic 3

Question 1

What are alcohols?

Answer 1

homologous series
- similar chemical properties
- show trend in physical properties (longer the chain, higher the boiling point)
- same functional group (C-OH)
- NOT hydrocarbons

Question 2

What are the 2 ways you can produce ethanol?

Answer 2

hydration of ethene
fermentation of glucose

Question 3

How does hydration of ethene work to produce ethanol?

Answer 3

extract crude oil from ground
fractional distillation
cracking - produces ethene
hydration (addition of steam)
phosphoric acid catalyst
high temp & pressure (300C, 60-70atms)
continuous process
C2H4 + H2O to CH3CH2OH

Question 4

How does fermentation of glucose work to produce ethanol?

Answer 4

extract sugar (glucose) from crops
add yeast (enzyme in yeast is a catalyst)
heat to 30C, no air, batch process
C6H12O6(aq) to 2CH3CH2OH(aq) +2CO2(g)

Question 5

What are the advantages of fermentation of glucose?

Answer 5

uses plants as raw material - renewable
gentle reaction conditions - cheaper

Question 6

What are the disadvantages of fermentation of glucose?

Answer 6

batch process - high labour cost
slow process
impure product - lower yield

Question 7

What are the advantages of hydration of ethene?

Answer 7

continuous process - cheaper manpower
fast rate of reaction
pure product - higher yield

Question 8

What are the advantages of hydration of ethene?

Answer 8

uses product made from crude oil - nonrenewable
very high temp.s & pressure required - expensive, dangerous

Question 9

What happens when you oxidise alcohols?

Answer 9

• oxidising agent = potassium dichromate in dilute sulphuric acid
• turns from orange to green
• heated
  C2H5OH + 2O to CH3COOH + H2O

Question 10

What happens in the dehydration of alcohols?

Answer 10

• removing water
• ethanol vapour is passed over hot aluminium oxide - catalyst
• OH group along with hydrogen on adjacent carbon is removed
  CH3CH2OH(g)to CH2CH2(g) + H2O(l)

Question 11

What are carboxylic acids?

Answer 11

homologous series
- trend in physical properties
- similar chemical properties
- all have -COOH functional group, allows them to act like other acids
- proton donors
- weak acids - only partially dissociate to release H+ ions

Question 12

What is ethanoic acid?

Answer 12

vinegar CH3COOH

Question 13

What are esters?

Answer 13

homologous series
- functional group -COO-
- produced when carboxylic acids & alcohols react, esterification reaction
carboxylic acid + alcohol to ester + water
- requires concentrated sulphuric acid catalyst
- esters are used in perfumes & flavourings = fruity smell

Question 14

What is condensation polymerisation?

Answer 14

• when 2 molecules react together & a small molecule (often water) is eliminated
• all condensation polymers can be reverted back to their monomers by hydrolysis (addition of water)
• the ester link forms between the -COOH- and the -OH-, the -COOH- loses the OH and the -OH just a H

Question 15

OH

Answer 15

alcohol

Question 16

COOH

Answer 16

carboxylic acid

Question 17

COO

Answer 17

ester