Fuels

Question 1

What is a hydrocarbon?

Answer 1

A compound made up of hydrogen and carbon only

Question 2

What is crude oil?

Answer 2

A mixture of hydrocarbons made up of molecules where carbon atoms are in chains or rings. It is a finite resource.

Question 3

What are the 6 different fractions of crude oil?

Answer 3

• Gasses
• Petrol
• Kerosine
• Diesel oil
• Fuel oil
• Bitumen

Question 4

What are gasses from crude oil used for?

Answer 4

Domestic heating and cooking

Question 5

What is petrol used for?

Answer 5

To fuel cars

Question 6

What is kerosine used for?

Answer 6

To fuel planes

Question 7

What is diesel oil used for?

Answer 7

To fuel trains and some cars

Question 8

What is fuel oil used for?

Answer 8

To fuel large ships and some power stations

Question 9

What is bitumen used for?

Answer 9

To surface roads and roofs

Question 10

Describe the fractional distillation of crude oil

Answer 10

• Crude oil is heated until it vaporises
• It travels up a fractionating column which is hotter at the bottom and colder at the top
• Each fraction of crude oil has a different boiling point and will condense at the right temperature
• Each fraction will then be separately drawn away from the column

Question 11

Do lighter hydrocarbons have higher or lower melting and boiling points?

Answer 11

Lower melting and boiling points

Question 12

Are the lighter or heavier hydrocarbons more flammable?

Answer 12

Lighter

Question 13

What are the products of the complete combustion of a hydrocarbon?

Answer 13

Carbon dioxide and water

Question 14

What are the products of the incomplete combustion of a hydrocarbon?

Answer 14

Carbon monoxide, carbon and water

Question 15

What are the dangers of carbon monoxide?

Answer 15

• It is toxic
• It can cause carbon monoxide poisoning

Question 16

What is the carbon produced in the incomplete combustion of a hydrocarbon in the form of?

Answer 16

Soot

Question 17

What are the dangers of appliances that use carbon compounds as fuels?

Answer 17

• Could cause incomplete combustion
• Soot can block boilers or cause fires
• Carbon monoxide is toxic

Question 18

How are oxides of nitrogen produced?

Answer 18

When fuels are burnt in engines the high temperatures cause the oxygen and nitrogen in the air to react

Question 19

What is cracking?

Answer 19

The breaking down of larger, saturated hydrocarbon molecules into smaller, more useful ones, some of which are unsaturated

Question 20

What are the reactants of cracking?

Answer 20

Alkanes

Question 21

What are the products of cracking?

Answer 21

Alkanes and alkenes

Question 22

What are the reasons for cracking?

Answer 22

• Helps to match the supply of fractions of crude oil with the demand
• It produces alkenes, which are used for feedstock

Question 23

What are the advantages of using hydrogen to fuel cars over petrol?

Answer 23

• Renewable source of fuel
• Does not produce toxic gas
• Does not produce greenhouse gasses

Question 24

What are the disadvantages of using hydrogen to fuel cars over petrol?

Answer 24

There are less hydrogen filling stations than petrol

Question 25

Compare chemical cells and fuel cells

Answer 25

Chemical cells produce voltage **until one of the reactants is used up**, fuel cells **produce voltage continuously** as long as there is a fuel (eg. hydrogen) and oxygen