Organic Chemistry

Question 1

What is crude oil

Answer 1

A mixture of hydrocarbons

Question 2

What does fractional distillation do and explain the process

Answer 2

Separates crude oil into fractions. Heated and oil evaporates… smaller molecules condense higher of the tower, larger molecules condensed low down into the tower.

Question 3

What is the role of bitumen

Answer 3

For road surfacing

Question 4

What is the role of fuel oil

Answer 4

For ships

Question 5

What is the role of diesel

Answer 5

Fuel for cars/lorries/busses

Question 6

What is the role of kerosene

Answer 6

Aircraft fuel

Question 7

What is the role of gasoline

Answer 7

Fuels for cars

Question 8

What is the trend in boiling point of the main fractions

Answer 8

The boiling point increases as the number of carbon atoms increases.

Question 9

What is the trend in viscosity of the main fractions

Answer 9

Viscosity increases as the number of carbon atoms increases

Question 10

What is the trend in colour of the main fractions.

Answer 10

The greater the number of carbon atoms the darker in colour.

Question 11

What is the trend in viscosity of the main fractions

Answer 11

Viscosity increases as the number of carbon atoms increase

Question 12

What happens when fuel is burned

Answer 12

It releases heat energy(exothermic reaction)

Question 13

What is complete combustion

Answer 13

Complete combustion happens in a reaction when there is enough oxygen available producing carbon dioxide and water.

Question 14

Give an example of a complete combustion reaction.

Answer 14

Methane + oxygen -> Carbon dioxide + water

CH4 +202 ->CO2 + 2H20

Question 15

What is incomplete combustion

Answer 15

Incomplete combustion happens in a reaction when there is not enough oxygen available

Question 16

What are possible products that can be produced in incomplete combustion

Answer 16

Carbon monoxide, carbon(soot), carbon dioxide and water

Question 17

Give an example of incomplete combustion

Answer 17

Ethane + oxygen -> carbon monoxide + water

C2H6 + 2.5 02 -> 2CO + 3H20

Question 18

How can carbon monoxide be produced

Answer 18

Via the incomplete combustion of fuels

Question 19

Give an example of carbon monoxide being produced in incomplete combustion

Answer 19

Propane + oxygen -> carbon monoxide + water

C3H8 + 3.5O2 -> 3CO + 4H20

Question 20

Why is carbon monoxide poisonous to humans

Answer 20

It reduces the capacity of the blood to carry oxygen

Question 21

What happens when fuels are burned in vehicle engines

Answer 21

High temperatures are reached

Question 22

What happens when high temperatures are reached in fuels

Answer 22

Nitrogen and oxygen react with the air to produce nitrogen oxides

Question 23

Give an example of nitrogen and oxygen reacting

Answer 23

 nitrogen + oxygen -> nitrogen oxides

N2 + O2 -> 2NO

Question 24

What can nitrogen oxides react with in the atmosphere

Answer 24

Water to produce HN03

Question 25

What are fossil fuels such as coal gas and oil made up from

Answer 25

Crude oil

Question 26

What are fossil fuels

Answer 26

Hydrocarbons

Question 27

What impurities can hydrocarbons contain

Answer 27

Sulphur

Question 28

If sulphur is present in a hydrocarbon, when burnt what can escape into the atmosphere

Answer 28

Sulphur dioxide

Question 29

Name the reaction between sulphur dioxide and oxygen

Answer 29

S + O2 -> SO2

Question 30

What can happen when acids form in the atmosphere

Answer 30

It can cause acid rain

Question 31

What natural and man-made materials can acid rain destroy

Answer 31

Acid rain can kill trees/plants, fish. It can also corrode limestone and marble since they are both made of calcium carbonate. Iron is also attacked by acid rain

Question 32

Give the chemical formula for calcium carbonate

Answer 32

CaCO3

Question 33

When sulphur dioxide is present in the atmosphere what can it sometimes react with

Answer 33

Water and oxygen to form sulphuric acid. 

Question 34

Give the chemical formula for sulphuric acid

Answer 34

(H2SO4)

Question 35

Give the named and balanced equation of sulphur dioxide reacting with water and oxygen

Answer 35

Sulphur dioxide + water + oxygen -> Sulphuric Acid 2SO2 + 2H2O + O2 -> 2H2SO4

Question 36

What happens if sulphur dioxide reacts with only water

Answer 36

A weak acid is produced called sulphurous acid

Question 37

Give the chemical formula for sulphurous acid

Answer 37

H2SO3

Question 38

What is cracking

Answer 38

Cracking involves a thermal decomposition of long chain alkanes into shorter chain alkanes and alkenes 

Question 39

Give an example of cracking

Answer 39

Decane -> octane + ethene C10H22 -> C8H18 + C2H4

Question 40

What are the thermal conditions of cracking

Answer 40

600°c

Question 41

Given example of catalysts used in cracking

Answer 41

Aluminium oxide Al2O3

Question 42

Yes or no crude oil contains excess amount of long chains of hydrocarbons.

Answer 42

Yes

Question 43

Why are shorter chain hydrocarbons in greater demand

Answer 43

As they take more time and are rarer than long chain hydrocarbons. For example petrol.

Question 44

What can cracking also produce

Answer 44

Alkenes used in making polymers and ethanol