C9: Crude oil and fuels

Question 1

What is a hydrocarbon?

Answer 1

A compound containing hydrogen and carbon atoms only

Question 2

What are some uses for crude oil?

Answer 2

Plastics
Petroleum
Medicines
Cosmetics

Question 3

Is crude oil finite or infinite?

Answer 3

Finite

Question 4

Where is crude oil found

Answer 4

Formed over millions of years from the remains of tiny sea creatures (namely plankton) that were buried in the mud.

Question 5

What is crude oil?

Answer 5

A mixture of hydrocarbons

Question 6

What is the general formula for alkanes?

Answer 6

CnH2n+2

Question 7

What are alkanes?

Answer 7

Saturated hydrocarbons
- contain maximum possible number of hydrogen atoms, containing only single covalent bonds

Question 8

What are the key properties of hydrocarbons?

Answer 8

Viscosity - how runny a liquid is
Volatility - how quickly a hydrocarbon reacts
Flammability - how easily a hydrocarbon combusts
Boiling point - how easily a hydrocarbon changes state

Question 9

How does viscosity vary among hydrocarbons?

Answer 9

As chains get longer, viscosity increases

Question 10

How does volatility vary with hydrocarbons?

Answer 10

As chains get longer, volatility decreases

Question 11

How does flammability vary with hydrocarbons?

Answer 11

As chains get longer, flammability decreases

Question 12

How does boiling point vary with hydrocarbons?

Answer 12

As chains get longer, boiling point increases

Question 13

What are some vehicles which run on hydrocarbon fuels?

Answer 13

Ships
Planes
Cars

Question 14

What happens during general combustion of hydrocarbons?

Answer 14

Carbon and hydrogen atoms react with oxygen to become oxidised

Question 15

What is complete combustion?

Answer 15

A hydrocarbon reacting in plentiful oxygen

Question 16

What is the equation for the complete combustion of hydrocarbons?

Answer 16

Alkane + Oxygen → Carbon dioxide + Water
e.g.
CH4 + 2O2 → CO2 + 2H2O

Question 17

What is the equation for incomplete combustion of hydrocarbons?

Answer 17

Alkane + Oxygen → Carbon/ Carbon monoxide + Water
e.g.
CH4 + 2O → C + 2H2O
CH4 + 3O → CO + 2H2O

Question 18

Why must the hydrocarbons in crude oil be separated?

Answer 18

In order to obtain useful products

Question 19

How are hydrocarbons separated from crude oil?

Answer 19

Fractional distillation, it is separated into fractions, containing hydrocarbons of similar structure

Question 20

Describe the process of fractional distillation

Answer 20

Crude oil is heated to high temperatures, until it is vaporised. It is the pumped into the fractionating column, which is hot at the bottom, and cooler at the top. The heaviest, unevaporated hydrocarbons are drained off of the bottom. The vapour the rises up the column, hydrocarbons will condense at different points within the column, upon reaching their boiling point. They are then drained out of the column

Question 21

What is the pattern of hydrocarbons condensing in the fractionating column?

Answer 21

Long chains condense towards the bottom, short chains condense towards the top

Question 22

What are fractions?

Answer 22

Containing a similar number of hydrocarbon atoms

Question 23

What are some fractions used for and give examples?

Answer 23

Fuels - petrol and diesel, kerosene, heavy fuel oil, liquified petroleum gas
Feedstock - solvents, lubricants, detergents, polymers

Question 24

What is the petrochemical industry?

Answer 24

Industries which use organic products for manufacture

Question 25

What is feedstock?

Answer 25

A chemical that's used in another chemical

Question 26

Why don't long-chain hydrocarbons make good fuels?

Answer 26

They are not very flammable

Question 27

What is cracking?

Answer 27

Converting a long chain hydrocarbon to a small chain hydrocarbon

Question 28

What are the products of cracking?

Answer 28

Shorter chain alkane and an alkane (usually ethene)

Question 29

What are the two methods of carrying out cracking?

Answer 29

Catalytic cracking Steam cracking

Question 30

What is catalytic cracking?

Answer 30

Using high temperatures (550C) and a catalyst (zeolite -to speed up the reaction)

Question 31

What is steam cracking?

Answer 31

Using higher temperatures (800C) and steam

Question 32

What is a homologous series?

Answer 32

A family of organic compounds that have the same functional group and similar chemical properties

Question 33

What is the general formula for alkenes?

Answer 33

CnH2n

Question 34

What are alkenes?

Answer 34

Unsaturated hydrocarbons - do not contain the maximum number of hydrocarbons and have at least one double carbon bond

Question 35

What is a functional group?

Answer 35

The section of (hydrocarbons) which reacts

Question 36

What are alkenes used for?

Answer 36

Feedstock

Question 37

What is the reactivity of alkenes as compared to alkanes?

Answer 37

Alkenes are more reactive because they have a functional group (are unsaturated)

Question 38

What are some pollutants produced when fuels burn?

Answer 38

Sulfur dioxide - acid rain Particulates - global dimming Carbon dioxide - global warming