C8: Fuels And Earth Science

Question 1

What are hydrocarbons?

Answer 1

Compounds that contain hydrogen and carbon atoms only

Question 2

What is crude oil?

Answer 2

• mixture of hydrocarbons
• contains molecules with rings or chains of carbon atoms
• finite resource

Question 3

Where can crude oil be found?

Answer 3

Under the sea and ground

Question 4

How can crude oil be separated?

Answer 4

Fractional distillation

Question 5

How does the process of fractional distillation work to separate crude oil?

Answer 5

• vaporised before it enters a fractionating column
• f.c is hotter at the bottom than the top
• vapours rise up and condense at different fractions depending on their boiling points
• hydrocarbons with low boiling points will be tapped off the top of the column and hydrocarbons with high boiling points will be tapped off at the bottom of the column

Question 6

Why is crude oil separated?

Answer 6

Unseparated crude oil isn’t very useful but the separated products (petroleum) are very useful

Question 7

Refinery gas is a fraction of crude oil, what are its common uses?

Answer 7

Heating and cooking

Question 8

What is a common use of kerosene?

Answer 8

Aircraft fuel

Question 9

Which fraction of crude oil is used for road surfacing and roofs?

Answer 9

Bitumen

Question 10

What is fuel oil most commonly used for?

Answer 10

Fuel for large ships and in some power stations

Question 11

Products from crude oil mostly belong to which homologous series?

Answer 11

Alkane homologous series

Question 12

What are the only products when a hydrocarbon fuel undergoes complete combustion?

Answer 12

Water and carbon dioxide

Question 13

When does incomplete combustion occurs?

Answer 13

When there is an insufficient supply of oxygen

Question 14

What are the products of incomplete combustion?

Answer 14

Carbon particulates - soot
Carbon monoxide
Water

Question 15

What are the problems with carbon monoxide?

Answer 15

• toxic gas
• colourless and odourless and if breathed in can cause death by preventing the red blood cells from carrying oxygen around the body

Question 16

How is acid rain produced?

Answer 16

• sulfur dioxide
• evaporates into the air
• it reacts with water In the clouds to form sulfuric acid

Question 17

What problems can acid rain cause?

Answer 17

• corrodes buildings and statues made of limestone
• kills/ damages the vegetation

Question 18

What problems are associated with oxides of nitrogen?

Answer 18

• pollutants
• produce acid rain with similar effects
• cause respiratory problems

Question 19

What’s a non-renewable fossil fuel found in natural gas?

Answer 19

Methane

Question 20

Are petrol, kerosene and diesel renewable fuels?

Answer 20

No they are non-renewable (finite resources)

Question 21

What is cracking?

Answer 21

Breaking down large hydrocarbons into smaller more useful ones

Question 22

What does saturated and unsaturated mean?

Answer 22

Saturated - only contains single bonds
Unsaturated - contains some C=C double bonds

Question 23

What type of reaction is cracking?

Answer 23

Thermal decomposition

Question 24

Why is cracking necessary?

Answer 24

The demand for shorter chain alkenes and alkanes is much greater than the demand for long chain alkanes

Question 25

What produced the gases that formed earths early atmosphere?

Answer 25

Volcanic activity

Question 26

How was earths early atmosphere formed?

Answer 26

• earths surface was molten with no atmosphere
• cooling caused land masses to solidify
• volcanoes formed on the land masses and released gases which formed the early atmosphere

Question 27

What was the earths early atmosphere thought to contain?

Answer 27

• little or no oxygen
• large amount of carbon dioxide
• water vapour
• small amounts of other gases

Question 28

How did oceans form?

Answer 28

Condensation of water vapour

Question 29

How did the amount of oxygen in the early earths atmosphere increase?

Answer 29

Growth of plants used carbon dioxide for photosynthesis and released oxygen, this increased the amount of oxygen and decreased the amount of carbon dioxide in the atmosphere

Question 30

What are greenhouse gases?

Answer 30

Various gases in the atmosphere (carbon dioxide, methane and water vapour) that absorb the heat radiated from earth

Question 31

What is the greenhouse effect?

Answer 31

• electromagnetic radiation from the sun passes through the earths atmosphere
• earth absorbs some radiation and warms up
• heat is radiated from the earth as infrared radiation
• some of the infrared radiation is absorbed by greenhouse gases in the atmosphere which warms the atmosphere

Question 32

How has human activity increased atmospheric carbon dioxide concentration?

Answer 32

• burning fossil fuels for energy releases carbon dioxide
• deforestation reduces the amount of photosynthesis occurring so less carbon dioxide is converted to oxygen

Question 33

What is the current composition of earths atmosphere?

Answer 33

Nitrogen - 78%
Oxygen- 21%
Carbon - 0.04%
Argon - 0.93%

Question 34

What are the effects of global warming?

Answer 34

• melting of polar ice caps
• flooding
• forest fires

Question 35

How has human activity increased the amount of methane in the atmosphere?

Answer 35

• raising livestock such as cows
• decay of organic waste in landfills sites

Question 36

How can the effects of global warming be mitigated?

Answer 36

• construct flood defences in areas of low lying land
• use of irrigation systems to provide water in drought
• produce alternative crops which are better adapted to the new environment