Crude Oil - Fractional Distillation & Combustion

Question 1

What is crude oil?

Answer 1

A mixture of hydrocarbons.

Question 2

What happens during the process of fractional distillation that separates crude oil into fractions?

Answer 2

• Vaporised crude oil is fed into the bottom of a column.
• The column is hot at the bottom and cold at the top.
• The fractions distill off at different levels (lower boiling points condense at the top, higher boiling points condense at the bottom).

Question 3

What is the order of the main fractions obtained from crude oil?

Answer 3

• Refinery gases (LPG)
• Gasoline
• Kerosene
• Diesel
• Fuel oil
• Bitumen

Question 4

What are refinery gases used for?

Answer 4

Heating and cooking - e.g. gas cylinders for barbecues.

Question 4

What is gasoline (petrol) used for?

Answer 4

Is is used as a fuel for cars.

Question 5

What is kerosene (paraffin) used for?

Answer 5

It is mainly used as aviation fuel for jet aircrafts.

Question 6

What is diesel oil used for?

Answer 6

It is mainly used as a fuel for lorries, buses and in some cars.

Question 7

What is fuel oil used for?

Answer 7

It is a heavy fraction used as a fuel for large industrial boilers, oil-fired power stations and ships.

Question 8

What is bitumen used for?

Answer 8

It’s used in road combustion and waterproof roof material.

Question 9

What is the trend in boiling points of the main fractions?

Answer 9

As the list goes down (refinery gases -> bitumen), the boiling points increase - bigger hydrocarbon chain length.

Question 10

What happens to the viscosity of the main fractions?

Answer 10

As the list goes down, there is an increase in the size of molecule and therefore an increase in viscosity.

Question 11

Why is carbon monoxide poisonous?

Answer 11

It binds to haemoglobin in blood irreversible and prevents oxygen transport.

Question 13

What is catalytic cracking?

Answer 13

A way in which long-chain alkanes are connected to alkenes and shorter-chain alkanes.
• temperature at 600-700°C
• silica/alumina used as a catalyst
• pressure at 70 atmospheres

Question 14

What happens in car engines with nitrogen and oxygen?

Answer 14

The temperature in car engines is high enough to allow nitrogen and oxygen from the air to react and form nitrous oxides (NO).

Question 15

Is a catalyst used in fractional distillation or cracking?

Answer 15

cracking

Question 16

Are alkenes in fractional distillation or cracking?

Answer 16

cracking

Question 17

Do decomposition reactions occur in fractional distillation or cracking?

Answer 17

cracking

Question 18

Are fuels obtained in fractional distillation or cracking?

Answer 18

both - fractional distillation and cracking

Question 19

Is separation the main purpose in fractional distillation or cracking?

Answer 19

fractional distillation