Section 6 - Organic Chemistry P2

Question 1

What are the different types of homologous series?

Answer 1

alkanes
alkenes
alcohols
carboxylic acids
esters

Question 2

What is the functional group of alcohols?

Answer 2

an oxygen hydrogen bond

Question 3

What is the functional group of carboxylic acids?

Answer 3

a carbon oxygen double bond and carbon hydroxide bond

Question 4

What is the functional group of esters?

Answer 4

a carbon oxygen double bond and a carbon oxygen bond

Question 5

What is the prefix/suffix of alcohols?

Answer 5

-ol

Question 6

What is the prefix/suffix of carboxylic acids?

Answer 6

-oic acid

Question 7

What is the prefix/suffix of esters?

Answer 7

Prefix: alkyl- -yl
Suffix: -anoate

Question 8

How could isomers be arranged differently?

Answer 8

The same atoms could be arranged into different functional groups

Question 9

What are the properties of isomers which have different functional groups?

Answer 9

Physical and chemical properties are both very different

Question 10

What is the general formula for alcohols?

Answer 10

CₙH₂ₙ₊₁OH

Question 11

What functional group do all alcohols contain?

Answer 11

-OH functional group

Question 12

What are the first four alcohols in the homologous series?

Answer 12

methanol
ethanol
propanol
butanol

Question 13

What different ways can the functional group be shown for an alcohol?

Answer 13

• the -OH group can be attached to different carbon atoms in the chain
• alcohols can have more than one -OH group

Question 14

What happens when something is oxidised?

Answer 14

It gains oxygen

Question 15

When alcohols are oxidised what happens?

Answer 15

• alcohols oxidise to form carboxylic acids

- for this you need an oxidising agent (such as potassium dichromate(VI) in dilute sulphuric acid

Question 16

What happens when ethanol is heated with acidified potassium dichromate(VI)?

Answer 16

Ethanoic acid is produced (CH₃COOH)

Question 17

What is microbial oxidation?

Answer 17

• some microorganisms are able to use alcohols as an energy source
• to do this they use oxygen in the air to oxidise alcohols, carboxylic acids are formed as a by-product

Question 18

When alcohols are burnt what occurs?

Answer 18

• when alcohols are burnt in enough oxygen they undergo complete combustion
• the products of this reaction are water and carbon dioxide

Question 19

How is ethene produced?

Answer 19

By cracking crude oil

Question 20

What will ethene and steam react together to produce?

And what type of reaction is it?

Answer 20

ethanol

an addition reaction

Question 21

How can ethanol be made?

Answer 21

• by reacting ethene and steam

- by fermenting glucose with yeast

Question 22

What conditions are needed for ethene to react with steam?

Answer 22

• temperature of 300°C
• pressure of 60-70 atmospheres
• phosphoric acid is used as a catalyst

Question 23

What is the trouble with producing ethanol from ethene and steam?

Answer 23

-at the moment it is a cheap process (ethene is fairly cheap and not much is wasted) BUT crude oil is a non-renewable resource which will start running out so it will become expensive to make ethanol from this

Question 24

What is alcohol in beer and wine made from?

Answer 24

Fermentation of glucose which is converted into ethanol and carbon dioxide by yeast

Question 25

What does yeast do in fermentation?

Answer 25

-yeast cells contain an enzyme (enzymes are naturally occurring catalysts)

Question 26

What are the conditions required for fermentation?

Answer 26

• mixture at about 30°C (optimum temperature for the enzymes, too hot would denature the enzymes)
• anaerobic conditions(no oxygen) - oxygen turns ethanol into ethanoic acid(vinegar)

Question 27

What are the advantages of making ethanol from fermentation?

Answer 27

-all the raw materials are all renewable sources
(sugar from sugar cane is grown as a major crop in several parts of the world)
(yeast is easy to grow)

Question 28

What are the disadvantages of making ethanol from fermentation?

Answer 28

• the ethanol you get from this process isn’t very concentrated, so it needs to be distilled to increase its strength
• it also needs to be purified

Question 29

What is the functional group of the carboxylic acid homologous series?

Answer 29

-COOH

has a C=O double bond and a C-OH bond, all coming off the same C

Question 30

What are the first four names of the carboxylic acids?

Answer 30

methanoic acid (HCOOH)
ethanoic acid (CH₃COOH)
propanoic acid (CH₃CH₂COOH)
butanoic acid (CH₃CH₂CH₂COOH)

Question 31

If a carboxylic acid reacts to form a salt, what do the name of the salt end in?

Answer 31

• anoate

e. g. ethanoate

Question 32

What do carboxylic acids in an aqueous solution react with metal carbonates to form?

Answer 32

salt + water + carbon dioxide

Question 33

What do aqueous carboxylic acids react with metals to form?

Answer 33

salt + hydrogen

Question 34

How are carboxylic acids used in the preparations of esters?

Answer 34

-carboxylic acids react with alcohols in the presence of an acid catalyst to form esters

Question 35

What is vinegar?

Answer 35

ethanoic acid dissolved in water

-vinegar is used for flavouring and preserving food

Question 36

alcohol + carboxylic acid –>

Answer 36

ester + water

an acid catalyst is usually used

Question 37

What functional group do esters have?

Answer 37

-COO-

Question 38

What do ester names end in?

Answer 38

-oate

Question 39

How do you name esters?

Answer 39

The alcohol forms the first part of the esters name, and the acid forms the second part of the esters name

Question 40

Describe a practical to make ethyl ethanoate:

Answer 40

• add 4 drops of concentrated sulphuric acid to a boiling tube using a dropping pipette
• add 10 drops of ethanoic acid
• add an equal volume of ethanol
• place the boiling tube in a beaker on a tripod
• heat using a bunsen burner until the water starts to boil then turn the bunsen burner off
• after 1 minute, remove the tube and allow it to cool
• pour the mixture into a test tube of sodium carbonate solution and mix, a layer of eater should form on the top (should smell sweet, like pear drops)

Question 41

What are the features of esters?

Answer 41

• many esters have pleasant smells

- volatile (they evaporate into gases very quickly)

Question 42

What are the uses of esters?

Answer 42

• used in perfumes

- used to make food flavourings

Question 43

What does condensation polymerisation involve?

Answer 43

Usually involves two different types of monomers

Question 44

How can polymers be made?

Answer 44

by condensation polymerisation

Question 45

What is the process of polymers being made from condensation polymerisation?

Answer 45

• the monomers react together and bonds form between them, making polymer chains
• each monomer has to contain at least two functional groups, one on each end of the molecule
• each functional group react with the functional group of another monomer, creating long chains of alternating monomers (each new bond that forms, a small molecule is lost)

Question 46

When do polyesters form?

Answer 46

Polyesters form when dicarboxylic acid monomers and diol monomers react together

Question 47

What two carboxylic acid groups are in the dicarboxlic acid monomers and diol monomers?

Answer 47

two alcohol (-OH) groups

Question 48

What is an ester link?

Answer 48

When the carboxylic acid group reacts with the alcohol group

Question 49

What are polyesters?

Answer 49

Polyesters are condensation monomers - each time an ester link is formed, a molecule of water is lost

Question 50

What are biopolyesters?

Answer 50

Biodegradable polyesters
-can be broken down by bacteria and other living organisms in the environment over time (they decompose and and don’t stay in landfill forever reducing the polymers’ pollutant effect

Question 51

What are examples of biopolyesters?

Answer 51

Some polyesters