C9 Crude Oil And Fuels

Question 1

What is the definition of a hydrocarbon?

Answer 1

A molecule comprised of only hydrogen and carbon atoms

Question 2

What is the general formula of an alkane?

Answer 2

C(n) H(2n+2)

Question 3

What type of molecules are alkanes?

Answer 3

Saturated

Question 4

What makes alkanes saturated?

Answer 4

They contain only C-C single bonds

Question 5

State the first four alkanes and their structures

Answer 5

Methane (CH4)
Ethane (C2H6)
Propane (C3H8)
Butane (C4H10)

Question 6

What is the viscosity of a liquid?

Answer 6

The “thickness of a liquid”

High viscosity liquids flow slower

Question 7

Describe how the size of a hydrocarbon affects its viscosity

Answer 7

As the size of the hydrocarbon chain increases, so does the viscosity

Question 8

Describe how the length of a hydrocarbon chain affects its flammability

Answer 8

The shorter the hydrocarbon chain, the greater its flammability

Question 9

Describe how the length of a hydrocarbon chain affects its boiling point

Answer 9

The shorter the hydrocarbon chain, the lower its boiling point

Question 10

What are the products of complete combustion?

Answer 10

Carbon dioxide and water

Question 11

What are the products of incomplete combustion?

Answer 11

Carbon monoxide and water

Question 12

Why does incomplete combustion occur?

Answer 12

Due to a limited oxygen supply

Question 13

What is combustion?

Answer 13

Burning in oxygen (to release energy)

Question 14

Describe the process of fractional distillation of crude oil

Answer 14

Firstly the crude oil is heated to a high temperature to boil it. The crude oil vapour is fed into the fractional distillation column, which is hotter at the bottom, and cooler at the top. The vapour rises up the column, and hydrocarbons condense when they reach their boiling point, and the liquid fractions are then removed. The remaining hydrocarbons continue moving up the column and condense when they reach their boiling points. Very short chain hydrocarbons have low boiling points and don’t condense, and are removed from the top of the column as gases

Question 15

What are Fractions?

Answer 15

Hydrocarbon chains with a similar number of carbon atoms

Question 16

What Hydrocarbons fractions are used to fuel cars?

Answer 16

Petrol and Diesel

Question 17

What Hydrocarbon fraction is used to fuel jets?

Answer 17

Kerosene

Question 18

What Hydrocarbon fraction is used to power ships?

Answer 18

Heavy fuel oil

Question 19

What Hydrocarbon fraction is used in camping stoves?

Answer 19

Liquified petroleum gas

Question 20

What is a feedstock?

Answer 20

A chemical used to make other chemicals

Question 21

What are some uses of hydrocarbons as feedstock?

Answer 21

• Lubricants
• Solvents
• Detergents
• Polymers

Question 22

Where is crude oil found?

Answer 22

In rocks

Question 23

Name the 2 key features of alkanes

Answer 23

• They have single bonds between carbon atoms

- They have the formula C(n) H(2n+2)

Question 24

What type of bond is between carbon atoms in an alkane?

Answer 24

A single covalent bond

Question 25

Why don't long chain hydrocarbons make good fuels?

Answer 25

As they aren't very flammable in comparison to short chain hydrocarbons

Question 26

What is the purpose of Cracking?

Answer 26

To make long chain hydrocarbons into shorter and more useful ones, that have a higher demand

Question 27

What are the 2 methods of cracking?

Answer 27

Catalytic and Steam

Question 28

Describe the conditions for catalytic cracking

Answer 28

High temperature and a catalyst | Hydrocarbon in a vapour

Question 29

Describe the conditions for steam cracking

Answer 29

High temperature and steam | Hydrocarbon in a vapour

Question 30

What type of bond is between carbon atoms in an alkene?

Answer 30

A double bond

Question 31

What is the general formula for the structure of alkenes?

Answer 31

C(n) H(2n)

Question 32

Why are alkenes useful?

Answer 32

They're used to make polymers and as starting materials to make other chemicals

Question 33

Compare the reactivity of alkanes with alkanes

Answer 33

Alkenes are more reactive

Question 34

What is the solution used to test for alkenes?

Answer 34

Bromine water

Question 35

Describe the test for Alkenes

Answer 35

Shake the alkene inside bromine water, which will turn from orange to colourless *colourless not clear*

Question 36

Which molecule releases more energy per mole when burnt, alkenes or alkanes?

Answer 36

Alkanes

Question 37

What type of reaction is involved in cracking?

Answer 37

A thermal decomposition reaction

Question 38

What type of hydrocarbon is an alkane?

Answer 38

A saturated hydrocarbon

Question 39

What type of hydrocarbon is an alkene?

Answer 39

An unsaturated hydrocarbon

Question 40

What kind of carbon - carbon bond is there in an unsaturated hydrocarbon?

Answer 40

A double bond