C7.2 Alcohols Flashcards

1
Q
  1. What are names of the first two alcohols?
A

-ethanol, methanol

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2
Q
  1. What is the molecular formula of ETHANOL?
A

C2H5OH

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3
Q
  1. What is the molecular formula of METHANOL?
A

CH3OH

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4
Q
  1. What is the general formula of alcohols?
A

CnH2n+1OH

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5
Q
  1. What is the functional group of alcohols?
A

-OH

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6
Q
  1. What causes the characteristic properties of alcohols?
A

-the presence of the –OH functional group

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7
Q
  1. How does ethanol compare in its physical properties with water and with alkanes?
A
  • soluble in water: alcohol (ethanol)
  • good solvent: alcohol (ethanol), water
  • boiling point: higher than alkanes but lower than water
  • state at room temperature: alcohol= volatile liquid, water= liquid, alkane= volatile gas
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8
Q
  1. What happens when alcohols burn in air?
A

-they produce carbon dioxide and water because of the presence of a hydrocarbon chain

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9
Q
  1. What are the reactions of sodium with ethanol, water and alkanes?
A
  • sodium + ethanol → sodium ethoxide + hydrogen
  • sodium + water → sodium hydroxide + hydrogen
  • sodium + alkanes DON’T REACT
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10
Q
  1. Why is there a limit to the concentration of ethanol solution that can be made by fermentation?
A

-when concentration of ethanol reaches 10-20% the yeast is killed by the ethanol so reaction stops

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11
Q
  1. What product is usually made by the process of formation to make ethanol?
A

-alcoholic drinks

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12
Q
  1. What is the process of producing ethanol by fermentation?
A
  • yeast converts sugars into ethanol (+carbon dioxide)

- enzyme zymase in yeast cells acts as catalyst for fermentation

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13
Q
  1. Why is it important to prevent oxygen getting into the fermentation process?
A

-oxygen converts ethanol into ethanoic acid= lower pH= enzymes stop working

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14
Q
  1. What happens when the fermented mixture is distilled?
A

-more concentrated ethanol solution= brandy/whisky

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15
Q
  1. What is the process of distillation?
A
  • ethanol solution in flask below fractioning column
  • solution heated= ethanol boils
  • ethanol vapour travels up and cools
  • anything with higher boiling point than ethanol cools and flows back to liquid= only pure ethanol reaches top column
  • ethanol vapour flows through condenser- cooled into liquid and collected
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16
Q
  1. What are the optimum conditions for making ethanol by fermentation of sugar with yeast (for enzyme zymase)?
A
  • temperature: 30⁰C (fastest rate of reaction without becoming denatured)
  • pH: 4
17
Q
  1. How can ethanol be made from waste biomass?
A

-genetically modified E. coli bacteria can convert cellulose in waste biomass into ethanol

18
Q
  1. What is waste biomass (and examples)?
A
  • parts of a plant that would normally be thrown away

- e.g. corn stalks, wood pulp, straw

19
Q
  1. Why can waste biomass not be fermented in the normal way?
A

-yeast can’t convert cellulose in waste biomass into ethanol

20
Q
  1. What are the optimum conditions for making ethanol from waste biomass?
A
  • temperature: 35⁰C

- pH: 6

21
Q
  1. What is the synthetic route for making ethanol?
A

-converting ethane (from oil or natural gas) into ethanol (via ethane)

22
Q
  1. What is used to make ethanol on an industrial scale and why?
A
  • fermentation too slow

- use ethane

23
Q
  1. What is ethane?
A

-a hydrocarbon from crude oil/natural gas

24
Q
  1. What is the process of making ethanol from ethane?
A
  • ethane ‘cracked’ (split) to form ethene and hydrogen gas

- ethene reacts with steam to make ethanol

25
Q
  1. What are the word equations that show the process of making ethanol from ethane?
A
  • ethane →ethene + hydrogen

- ethane + steam → ethanol

26
Q
  1. What is the formula for ethene?
A

-C2H4

27
Q
  1. What are the industrial conditions for the process of making ethanol from ethane?
A
  • pressure= 70 atmospheres
  • temperature= 300⁰
  • catalyst= phosphoric acid
28
Q
  1. What are the different processes for producing ethanol?
A
Natural:
-fermentation 
-biomass
Industrial:
-Ethene
29
Q
  1. What are uses of methanol?
A

-antifreeze, solvent, fuel

30
Q
  1. What are uses of ethanol?
A
  • alcoholic drinks, biofuel