C10 - Organic reactions

Question 1

What are alkenes?

Answer 1

• Hydrocarbons with a double carbon-carbon bond

Question 2

What is the general formula for alkenes?

Answer 2

CnH2n

Question 3

Why are alkene molecules unsaturated?

Answer 3

Contain two fewer hydrogen atoms than the alkane with the same number of carbon atoms

Question 4

What are the first four members of the homologous series of alkenes known as?

Answer 4

• Ethene
• Propene
• Butene
• Pentene

Question 5

What is the functional group of the alkenes?

Answer 5

C=C

Question 6

What happens when alkenes react with oxygen?

Answer 6

Burn with a smoky flame due to incomplete combustion

Question 7

What happens when alkenes react with hydrogen, water and the halogens?

Answer 7

The atoms are added across the carbon carbon double bond so that the double bond becomes a single carbon-carbon bond

Question 8

Alkene + hydrogen —>

Answer 8

Alkane
- Hydrogenation, needs catalyst

Question 9

Alkene + water —>

Answer 9

Alcohol
- Hydration, 300 degrees, needs catalyst

Question 10

Alkene + halogen —>

Answer 10

Halogenoalkane
- Spontaneous

Question 11

What is the functional group of alcohols?

Answer 11

-OH

Question 12

What are the first four members of the alcohol series?

Answer 12

• Methanol
• Ethanol
• Propanol
• Butanol

Question 13

What happens when alcohol burns in air?

Answer 13

Complete combustion to make carbon dioxide and water

Question 14

What happens when alcohols react with sodium?

Answer 14

They react to produce a sodium alkoxide and hydrogen

Question 15

What happens when sodium is added to water?

Answer 15

The shortest hydrocarbon chains can mix to form a solution

Question 16

What happens when alcohols react with oxidising agents?

Answer 16

Carboxylic acids and water are formed

Question 17

What are the uses of the first 3 alcohols?(2)

Answer 17

• Fuels - highly flammable and can ignite easily
• Solvents - marker pens, medicines, and deodorants, perfurmes

Question 18

How is ethanol produced from sugar?

Answer 18

Sugar solutions are fermented with yeast

Question 19

What are the 3 conditions for fermentation of sugar?

Answer 19

• Sugar dissolved in water with yeast
• air lock to allow carbon dioxide out(anaerobic conditions)
• warm temperature

Question 20

What is the functional group of carboxylic acids?

Answer 20

-COOH

Question 21

What is the general formula for carboxylic acids?

Answer 21

CH3COOH

Question 22

What are the first four members of the carboxylic acids?

Answer 22

• Methanoic
• Ethanoic
• Propanoic
• Butanoic

Question 23

What happens when the carboxylic acids react with carbonates?

Answer 23

They form a salt, water and carbon dioxide gas

Question 24

What happens when the carboxylic acids dissolve in water?

Answer 24

They dissolve to form acidic solutions

Question 25

What happens when the carboxylic acids react with alcohols?

Answer 25

They react to make esters and water

Question 26

Why are carboxilic acids weak acids?(2)

Answer 26

- Their solutions do not contain many hydrogen ions compared with a strong acid - Very few molecules are ionised

Question 27

What is the name of an ester?

Answer 27

Ethyl ethanoate

Question 28

Describe how ethanol can be produced from alkenes?(4)

Answer 28

- Alkene is mixed with steam - Very high temperatures - Presence of a catalyst - Heat the gas + high pressure

Question 29

Evaluate the use of crude oil and sugar to produce ethanol(SUGAR)(4A AND 4D)

Answer 29

Advantages: - Cheaper to buy - Renewable resource - Carbon neutral - Low technology process Disadvantages: - Batch process if slow - Large area of land to grow crops needed - Labour intensive - May be impure

Question 30

Evaluate the use of crude oil and sugar to produce ethanol(CRUDE OIL)(2A AND 4D)

Answer 30

Advantages: - Fast process - Ethanol is pure Disadvantages: - Non renewable - More expensive - Risk of oil spillages - Not carbon neutral