Organic chem

Question 1

Alkanes (4)

Answer 1

• no functional grp
• CnH2n+2
• saturated hydrocarbons
• carbon-carbon single bonds

Question 2

Alkenes (3)

Answer 2

• Carbon-carbon double bond (functional grp)
• CnH2n
• unsaturated hydrocarbons

Question 3

Alcohols (3)

Answer 3

• Hydroxyl grp
• CnH2n+1OH
• contain carbon, hydrogen and oxygen

Question 4

Carboxylic acids (3)

Answer 4

• Carboxyl grp
• CnH2n+1COOH
• for first member in the series, only carbon atom found in the —COOH group

Question 5

Organic compounds in the same homologous series (3)

Answer 5

• same functional group
• similar chemical properties
• show a gradual change in their physical properties down the series

Question 6

Prefixes (4)

Answer 6

Meth ~
Eth ~
Prop ~
But ~

(Muslims Eat Pork Belly)

Question 7

petroleum (3)

Answer 7

• source of energy
• also called crude oil
• naturally occurring mixture of hydrocarbons (mainly alkanes)

Question 8

Natural gas

Answer 8

• source of energy
• made up of methane (70-90%) and other short chain alkanes (ethane, propane, butane)

Question 9

separation of petroleum (2)

Answer 9

• by fractional distillation
• fractions:
  Petroleum gas
  Petrol (gasoline)
  Naphtha
  Kerosene (paraffin)
  Diesel Oil
  Lubricating Oil
  Bitumen

(Peter Piper Never Kills Dead Lying Bugs)

Question 10

Petroleum gas

Answer 10

Fuel for cooking and heating

Question 11

Petrol (gasoline)

Answer 11

Fuel for car engine

Question 12

Naphtha

Answer 12

Feedstock (raw material) for petroleum industry (produces plastics, detergents etc)

Question 13

Kerosene (paraffin)

Answer 13

Fuel for aircraft engines, cooking and heating

Question 14

Diesel Oil

Answer 14

Fuel for engines in buses, lorries and trains

Question 15

Lubricating Oil (2)

Answer 15

• Lubricating machines
• Making waxes and polishes

Question 16

Bitumen (2)

Answer 16

• Paving road surfaces
• Roofing

Question 17

physical properties of alkanes (6)

Answer 17

• low MP and BP
• insoluble in water
• soluble in organic solvents
• mp and bp increase down the series
• more viscous down the series
• flammability increases down the series

Question 18

chemical properties of Alkanes (3)

Answer 18

• complete combustion in excess oxygen, forming CO2 + H2O
• incomplete combustion in limited oxygen, forming CO + soot + H2O
• substitution reaction with halogens in the presence of UV light, e.g. chloromethane

Question 19

physical properties of alkenes (2)

Answer 19

• low mp and bp
• mp and bp increase down the series

Question 20

Chemical properties of alkenes (6)

Answer 20

• complete combustion in excess oxygen, forming CO2 + H2O
• incomplete combustion in limited oxygen, forming CO + soot + H2O
• Hydrogenation
• Bromination
• Hydration
• Addition polymerisation

Question 21

Hydrogenation (2)

Answer 21

• The addition of hydrogen to alkenes to form alkanes
• Conditions: 200 celcius, nickel catalyst

Question 22

Bromination (3)

Answer 22

• The addition of bromine to alkenes
• Used to differentiate alkanes and alkenes based on colour change (presence of unsaturated hydrocarbons)
• Alkanes do not decolourise bromine while Alkenes do

Question 23

Hydration (2)

Answer 23

• The addition of steam to alkenes to form alcohols
• Conditions: 300 celcius, 60 atm, phosphoric(V) acid catalyst (H3PO4)

Question 24

Addition polymerisation (2)

Answer 24

• Alkene molecules (monomers) react with each other to form a long molecule called a polymer.
• Conditions: high temperature and pressure, catalyst

Question 25

Cracking (3)

Answer 25

- the breaking down of long-chain hydrocarbons into smaller hydrocarbons or hydrogen - cracking to obtain alkene from petroleum - catalyst required for catalytic cracking