C8 Fuels and Earth Science

Question 1

How is crude oil formed?

Answer 1

From the remains of plants and animals over millions of years

Question 2

What is a hydrocarbon?

Answer 2

Compounds containing only hydrogen and carbon

Question 3

How is crude oil separated?

Answer 3

1. The oil is vaporised
2. It then enters a fractionating column
3. In the column, there is a temperature gradient
4. The longer hydrocarbons have higher boiling points so they turn into liquids and drain out at the bottom
5. The shorter length hydrocarbons have lower boiling points so they turn to liquid and drain near the top

Question 4

What is the order of the hydrocarbon fractions (smallest to largest)?

Answer 4

1. Natural gas
2. Petrol
3. Kerosene
4. Diesel oil
5. Fuel oil
6. Bitumen

Question 5

What are the properties of a homologous series?

Answer 5

1. Same general formula
2. Similar chemical properties
3. Trends in physical properties

Question 6

What happens to the hydrocarbons as the chain length increases?

Answer 6

1. Higher boiling point
2. Harder to ignite
3. Less viscous

Question 7

What is incomplete combustion?

Answer 7

Where there isn’t enough oxygen for complete combustion, forming carbon monoxide

Question 8

What happens if you breathe in carbon monoxide?

Answer 8

It stops oxygen from binding to red blood cells, leading to fainting/death

Question 9

What happens when sulfur is combusted?

Answer 9

It forms sulfur dioxide which mixes with cloud causing acid rain. This damages stone buildings and can corrode metal

Question 10

How is nitrogen oxide produced?

Answer 10

The energy released from combustion reactions cause nitrogen and oxygen to mix in the air, causing breathing difficulties

Question 11

What are the uses for natural gas?

Answer 11

Heating

Question 12

What are the uses for petrol?

Answer 12

Cars

Question 13

What are the uses for kerosene?

Answer 13

Aircraft fuel

Question 14

What are the uses of diesel oil?

Answer 14

Larger vehicles like trains

Question 15

What are the uses of fuel oil?

Answer 15

Power stations

Question 16

What are the uses of bitumen?

Answer 16

Surfacing roads

Question 17

Why do we crack hydrocarbons?

Answer 17

There is more demand for shorter chains than longer chains

Question 18

What are the conditions for cracking?

Answer 18

1. 700C
2. 70atm
3. Aluminium oxide catalyst

Question 19

What was phase 1 of the atmosphere?

Answer 19

1. Little of no oxygen
2. Volcanoes constantly erupted releasing carbon dioxide and water vapour
3. There was a small amount of steam, methane and ammonia
4. The water vapour later condensed to form the oceans

Question 20

What was phase 2 of the atmosphere?

Answer 20

1. Lots of CO2 dissolved into oceans
2. Nitrogen was produced by ammonia reacting with oxygen and by denitrifying bacteria
3. Plants evolved, removing CO2 and producing O2 by photosynthesis

Question 21

What was phase 3 of the atmosphere?

Answer 21

1. The build up of oxygen created the ozone layer which blocked harmful rays from the Sun and even more complex organisms to evolve
2. There’s virtually no CO2 left now

Question 22

What is the test for oxygen?

Answer 22

Take a glowing splint. If the gas is oxygen it will relight

Question 23

How does the greenhouse effect work?

Answer 23

1. The Earth re-radiates some of the radiation it absorbs as longer wavelength IR radiation
2. Some of this IR radiation is absorbed by greenhouse gases and some is re-emitted back towards the earth by greenhouse gases and some is re-emitted back towards space
3. Because the IR radiation is thermal radiation its absorption and re-emission by greenhouse gases helps keep the Earth warm