C15 - Organic Reactions (PAPER 2)

Question 1

What is a homologous series

Answer 1

a group of compounds with the same functional group

Question 2

What is a functional group

Answer 2

a group of atoms that determines the properties of a compound

Question 3

What are alkenes (homologous series)

Answer 3

a homologous series with a double Carbon-carbon bond (C=C)

Question 4

What is the general formula for alkenes

Answer 4

C(n)H(2n)

Question 5

How are alkenes formed

Answer 5

through cracking of alkanes

Question 6

What are the two main uses of alkenes

Answer 6

• formation of polymers
• a chemical feedstock

Question 7

What happens in the combustion reactions of an alkene, which is more likely
- How does it compare to that of alkanes

Answer 7

• complete combustion produces carbon dioxide and water
• incomplete combustion produces a smoky yellow flame, carbon monoxide / carbon and water
• incomplete combustion is more likely than complete combustion for alkenes
• produces less energy per mole than alkanes

Question 8

Are alkenes saturated or unsaturated
- Why

Answer 8

unsaturated
- because they have double bonds, so atoms can be added to the molecule by breaking the double bond

Question 9

What is the product of the reaction between halogens and alkenes
- what is the name of the product when propene and bromine

Answer 9

halogenation
- dibromo propane

Question 10

What is the product of the reaction of an alkene and hydrogen
- what is the name of the process

Answer 10

alkane
- hydrogenation

Question 11

What is formed when an alkene reacts with steam
- under what conditions must this be done

Answer 11

an alcohol
- high temperature, high pressure and in the presence of a catalyst (phosphoric acid)

Question 12

What are alcohols

Answer 12

a homologous series with an -OH group

Question 13

How are alcohols produced
- What are the formulas

Answer 13

glucose –> ethanol + carbon dioxide
C6 H12 O6 —> 2 C2 H5OH

(fermentation)

alkene + steam —-> alcohol

(alkenes and steam)

Question 14

What conditions are required to produce alcohols by fermenting

Answer 14

sugar solution with yeast mixed in, warm, sealed vessel

Question 15

What are the first four alcohols

Answer 15

methanol, ethanol, propanol, butanol

Question 16

What are 3 uses of alcohols

Answer 16

• ethanol is used in alcoholic drinks
• solvents (as they are easy soluble) (miscible)
• perfumes, aftershaves and mouthwashes

Question 17

What happens in the combustion of alcohols

Answer 17

short alcohols combust easily with a blue flame, produces carbon dioxide and water

Question 18

What are the products of the reaction between sodium and alcohol
- what happens when this is added to water

Answer 18

hydrogen and an alkoxide
- a strongly alkaline solution is produced

Question 19

What organic product is formed through the oxidation of alcohols
- what compounds do the alcohols react with

Answer 19

carboxylic acids
- oxidising agents

Question 20

Name an oxidising agent

Answer 20

acidified potassium dichromate

Question 21

What are carboxylic acids

Answer 21

a homologous series with a -COOH group

Question 22

How are carboxylic acids formed

Answer 22

oxidisation of alcohols

Question 23

What is a use of ethanoic acid

Answer 23

used in vinegar

Question 24

What are the first four carboxylic acids called

Answer 24

methanoic acid, ethanoic acid, propanoic acid, butanoic acid

Question 25

What do carboxylic acids form when reacted with a metal carbonate

Answer 25

salt, carbon dioxide and water

Question 26

What is formed when a carboxylic acid reacts with an alcohol
- what is required for this reaction

Answer 26

water and esters
- sulfuric acid as a catalyst (usually concentrated)

Question 27

What is the product between methanol and ethanoic acid

Answer 27

methyl ethanoate

Question 28

What happens when carboxylic acids are added water

Answer 28

the carboxylic acids become partially ionised to form weakly acidic solutions - they are weak acids