Fuels and hydrocarbons

Question 1

What is the definition of a hydrocarbon?

Answer 1

A substance that contains ONLY hydrogen and carbon

Question 2

What is the general formula for alkanes

Answer 2

CnH2n+2

Question 3

What is the general formula for alkenes

Answer 3

CnH2n

Question 4

What are fractions?

Answer 4

Different substances we get from distilling crude oil

Question 5

How are hydrocarbons in crude oil bound?

Answer 5

A ring

Question 6

What are the 2 main ways to dispose of polymers

Answer 6

Landfill + combustion

Question 7

What does incomplete combustion create?

Answer 7

Carbon, which then can form carbon monoxide

Question 8

What does complete combustion of alkanes always create?

Answer 8

ONLY water and carbon dioxide

Question 9

Heat for cracking?

Answer 9

600-700°C

Question 10

Catalyst used for cracking?

Answer 10

Aluminium or silica oxide

Question 11

What does poly- added before an alkene mean?

Answer 11

It is the repeat unit

Question 12

What will happen when you add ALKENES to bromine water?

Answer 12

Bromine water will turn from orange to colourless

Question 13

What will happen when you add ALKANES to bromine water?

Answer 13

The bromine water WILL NOT CHANGE COLOUR

Question 14

What is the definition of cracking?

Answer 14

The process of breaking down longer-chain hydrocarbons into shorter-chain alkanes and alkenes

Question 15

What are 2 features of the same homologous group?

Answer 15

• Similar chemical properties
• Same functional group

Question 16

What type of reaction is cracking?

Answer 16

Cracking is a thermal decomposition reaction

Question 17

What is crude oil?

Answer 17

A complex mixture of hydrocarbons

Question 18

Is the top of an oil fractionating column hotter or cooler than the bottom of an oil fractionating column?

Answer 18

The top is cooler than the bottom of the column

Question 19

What happens to a liquid during its separation from a mixture by distillation?

Answer 19

It evaporates and then condenses

Question 20

In comparison to large hydrocarbons, what are the properties of small hydrocarbons?

Answer 20

They are more volatile, flammable and have a lower boiling point

Question 21

What is really the only reactions for hydrocarbons?

Answer 21

Combustion

Question 22

What is a liquid fossil fuel (like crude oil) formed from?

Answer 22

The remains of microscopic dead plants and animals that lived in the sea.

Question 23

What does volatile mean?

Answer 23

A substance boils easily

Question 24

Are ALKANES saturated or unsaturated?

Answer 24

They are saturated

Question 25

Are ALKENES saturated or unsaturated?

Answer 25

They are unsaturated

Question 26

Where are the most viscous hydrocarbons likely to leave the fractionating column at?

Answer 26

The bottom

Question 27

What is the name by which we separate crude oil into useful components?

Answer 27

Fractional distillation

Question 28

What are the products of cracking?

Answer 28

Alkanes and alkenes

Question 29

What is polymerisation?

Answer 29

When many small alkene molecules (monomers) join together to form polymers