5.4 - Organics II Flashcards

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1
Q

What is an alcohol?

A

Alcohols are organic molecules containing an —OH functional group.

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2
Q

How are the names of alcohols formed?

A
  • The start of the name shows how many carbon atoms it has.
  • The end of the name is ‘-ol’ to show it’s an alcohol.
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3
Q

How do we show where the —OH group is attached to the alcohol?

A

We include a number in the name to indicate where it’s attached

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4
Q

What are the methods used to produce alcohols?

A

Hydration of Ethene
Fermentation of Glucose

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5
Q

What conditions are needed for the hydration of ethene?

A
  • 300 degrees C
  • 65 atm pressure
  • Phosphoric acid (H3PO4) catalyst
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6
Q

How is ethene provided in ethene hydration?

A

Crude oil provides the ethene.

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7
Q

Advantages of ethene hydration?

A
  • Makes pure ethanol.
  • Can run continuously.
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8
Q

Disadvantages of ethene hydration?

A
  • Conditions require lots of energy.
  • Non-renewable raw material used.
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9
Q

What conditions are needed for the fermentation of glucose?

A
  • Yeast (provides enzymes)
  • 30 degrees C: enzymes’ optimum temperature
  • Anaerobic (no air): prevents oxidation
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10
Q

Where do the glucose come from in the fermentation of glucose?

A

Sugar cane provides the glucose

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11
Q

Advantages of fermenting glucose?

A
  • Renewable raw material used.
  • Conditions not energy-intensive
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12
Q

Disadvantages of fermenting glucose?

A
  • Makes impure ethanol.
  • Must be done in individual batches
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13
Q

How can ethanol be oxidised?

A
  1. Combustion
  2. Microbial Oxidation
  3. Chemical oxidation
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14
Q

What happens when ethanol is combusted?

A

Ethanol tends to combust completely because of the oxygen atom in the —OH group.
This results in a non-luminous, blue flame.

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15
Q

What happens when ethanol oxidised via microbial methods?

A

Many micro-organisms, such as bacteria and fungi, can use the oxygen in the air to oxidise ethanol into ethanoic acid. This process can only happen if aerobically

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16
Q

How do we represent the microbial use of oxygen?

A

Using the [O] symbol

17
Q

What do we heat ethanol with if we want to oxidise it chemically?

A

We heat it with a mixture of:
* Potassium dichromate(VI) (K2Cr2O7)
* Dilute sulfuric acid (H2SO4)

18
Q

What does chemical oxidation form?

A

It forms ethanoic acid

19
Q

What colour change can be seen with the chemical oxidisation of ethanol?

A

Orange → Green

20
Q

What are carboxylic acids?

A

Carboxylic acids are organic molecules containing an —COOH functional group.

21
Q

How are the names of carboxylic acids formed?

A
  • The start of the name shows how many carbon atoms it has.
  • The end of the name is ‘—oic acid’ to show it’s a carboxylic acid.
22
Q

An example of an aqueous solution of ethanoic acid?

A

Vinegar

23
Q

What happens when a carboxylic acid loses its H+?

A

The name changes from ‘-oic acid’ in the carboxylic acid to ‘-oate’ in the salt because it becomes negatively charged.

24
Q

What is an ester?

A

Esters are a family of organic molecules which form when a carboxylic acid and an alcohol join together by losing an H2O molecule.

25
Q

What is the functional group of an ester?

A

—COO—

26
Q

Equation for the formation of an ester?

A

Carboxylic acid + Alcohol → Ester + Water

27
Q

What happens when ethanoic acid and ethanol react?

A

Ethyl ethanoate and water is produced.

28
Q

What are the names given to the process that forms esters?

A

Condensation (because of the production of water vapour)
OR
Esterification (because an ester is formed)

29
Q

How would we prepare an ester?

A
  1. Mix the carboxylic acid and alcohol together.
  2. Add a few drops of concentrated sulfuric acid (H2SO4). (this acts as a catalyst for the reaction)
  3. Warm it for a while.
  4. Tip the mixture into sodium carbonate (Na2CO3) solution.
    (this neutralises the sulfuric acid catalyst, which is otherwise really corrosive)
30
Q

What are esters used for?

A

Food flavourings and perfumes

31
Q

What is a polyester?

A

A polyester is a polymer made of lots of molecules joined together in a chain by ester groups.

32
Q

How do we make a polyester?

A

To make a polyester, you need to mix two types of monomers

33
Q

What two monomers are needed to make a polyester?

A

A dicarboxylic acid (has -COOH at both ends)
AND
A diol (has -OH at both ends)

34
Q

What this type of polymerisation called?

A

condensation polymerisation

35
Q

What are the uses of polyestsers?

A

Clothing and Sportswear.

36
Q

What are bio-polyesters?

A

Biodegradable polyesters

This means microbes such as bacteria and fungi can use enzymes to break down the polymer into its monomers and use them as an energy supply.