Organic Chemistry Fuels

Question 1

Sources of fuels

Answer 1

1. Petroleum (crude oil)

2. Natural gas

Question 2

Petroleum (crude oil)

Answer 2

A naturally occurring mixture of hydrocarbons (mainly alkanes)

Thick, black liquid

Non-renewable resource (limited)

Question 3

Natural gas

Answer 3

A mixture of many gases, mainly made up of methane and other short-chain alkanes such as ethane, propane and butane

Question 4

Hydrocarbons

Answer 4

Compounds made up of only carbon and hydrogen

Question 5

Complete combustion

Answer 5

Complete combustion occurs when there is sufficient oxygen present

Complete combustion of hydrocarbons produces carbon dioxide, water and a lot of heat

Question 6

Incomplete combustion

Answer 6

Incomplete combustion occurs when there is insufficient oxygen present

Carbon monoxide and soot obtained

Question 7

Fractions

Answer 7

Lighter fractions —> smaller hydrocarbons 
Heavier fractions —> bigger hydrocarbons 
Petroleum gas
Petrol (gasoline)
Naphtha 
Kerosine (paraffin)
Diesel oil
Lubricating oil
Bitumen

Question 8

Petroleum gas

Answer 8

USES
Fuel for cooking and heating
APPROXIMATE BOILING POINT RANGE
Below room temperature
APPROXIMATE NUMBER OF CARBON ATOMS PER MOLECULE
1-4

Question 9

Petrol (gasoline)

Answer 9

USES
Fuel for motorcars
APPROXIMATE BOILING POINT RANGE
35-75
APPROXIMATE NUMBER OF CARBON ATOMS PER MOLECULE 
5-10

Question 10

Naphtha

Answer 10

USES
Feedstock for making petrochemicals such as plastics and detergents
APPROXIMATE BOILING POINT RANGE
70-170
APPROXIMATE NUMBER OF CARBON ATOMS PER MOLECULE
8-12

Question 11

Kerosine (paraffin)

Answer 11

USES
Fuel for aircraft engines, cooking using oil stoves and heating
APPROXIMATE BOILING POINT RANGE
170-250
APPROXIMATE NUMBER OF CARBON ATOMS PER MOLECULE
10-16

Question 12

Diesel oil

Answer 12

USES
Fuel for diesel engines in trains, buses and lorries
APPROXIMATE BOILING POINT RANGE
250-340
APPROXIMATE NUMBER OF CARBON ATOMS PER MOLECULE
15-25

Question 13

Lubricating oil

Answer 13

USES
For lubricating machines;for making waxes and polishes
APPROXIMATE BOILING POINT RANGE
350-500
APPROXIMATE NUMBER OF CARBON ATOMS PER MOLECULE
19-35

Question 14

Bitumen

Answer 14

USES
For making road surfaces and roofing
APPROXIMATE BOILING POINT RANGE
Over 580
APPROXIMATE NUMBER OF CARBON ATOMS PER MOLECULE 
More than 70

Question 15

Is each fraction pure?

Answer 15

No. Each fraction consists of hydrocarbons with similar range of carbon atoms per molecule

Question 16

Relationship

Answer 16

Boiling point increases

Number of carbon atoms per molecule increases

Question 17

Fractional distillation of petroleum in an oil refinery

Answer 17

1. Petroleum is heated into a vapour in the furnace
2. The vapour is passed into the fractionating column
3. The hot vapour cools and condenses as it rises up the column
4. Lighter fractions with lower boiling points are collected at the top of the column as gases
5. Heavier fractions with higher boiling points are collected at the bottom of the column as residue

Question 18

Environmental issues of combustion of fuels

Answer 18

1. Greenhouse effect

2. Air pollution