Uses And Cracking Of Crude Oil

Question 1

What are some modern things crude oil is used for?

Answer 1

fuel for modern transport such as cars, trains and planes e.g. diesel, kerosene, heavy fuel oil and liquid petroleum gas

Question 2

What do the petrochemical industry do?

Answer 2

They use some of the hydrocarbons from crude oil as feedstock to make new compounds for use in things like polymers, solvents, lubricants and detergents

Question 3

What are organic compounds?

Answer 3

•compounds containing carbon atoms
•all the products you get from crude oil are examples of organic compounds

Question 4

Why are we able to get a large variety of products from crude oil?

Answer 4

•carbon atoms can bond together to form different groups called homologous series
•these groups contain similar compounds with many properties in common. Alkanes and alkenes are both examples of homologous series

Question 5

How are longer alkane molecules produced from fractional distillation turned into smaller, more useful ones?

Answer 5

By cracking

Question 6

What are some uses of products of cracking?

Answer 6

They can be used for fuels such as petrols for cars and paraffin for jet fuel

Question 7

Apart from alkanes what is another product produced from cracking?

Answer 7

alkenes

Question 8

What is the difference between alkenes and alkanes and what are alkenes used for?

Answer 8

•alkenes are more reactive than alkanes
•they’re used as starting material when making lots of other compounds and can be used to make polymers

Question 9

How can you test for alkenes?

Answer 9

•when orange bromine water is added to an alkane no reaction will happen and it will stay bright orange
•when added to an alkene the bromine reacts with alkene to make a colourless compound so the bromine water is decolourised

Question 10

What is cracking?

Answer 10

A thermal decomposition reaction breaking molecules down by heating them

Question 11

What are the different methods of cracking?

Answer 11

•catalytic cracking
•steam cracking

Question 12

What happens during catalytic cracking?

Answer 12

1)the first step is to heat long chain hydrocarbons to vaporise them
2) the vapour is passed over a hot powdered aluminium oxide catalyst
3)the long chain molecules then split apart on the surface of the specks of the catalyst

Question 13

What is steam cracking?

Answer 13

*this is cracking hydrocarbons by cracking them
*the first step is to mix them with steam and then heat them to a very high temperature

Question 14

What is the general formula for alkenes?

Answer 14

CnH2n

Question 15

Balance this chemical equation for cracking:
C6H14 —> C2H4 + ?

Answer 15

carbons: 6-2= 4
Hydrogen: 14-4=10
therefore, ?= C4H10 (butane)

Question 16

Why is cracking used?

Answer 16

•to produce smaller hydrocarbon molecules
•fractions with shorter carbon chains are more flammable, more volatile and less viscous than longer ones.
•We need more of these fuels than we can provide and we have more longer chain fuels than we need