Fossil Fuels

Question 1

what are different types of fossil fuels

Answer 1

Natural gas (methane) 55 MJ/kg
– Oil 45 MJ/kg
– Coal 30 MJ/kg

Question 2

how are fossil fuels made

Answer 2

decomposition of organic material in a reducing environment, e.g. stagnant swamp, bottom of a lake.

Question 3

What are the 4 types of organic materials

Answer 3

• Humus humicmaterialinsoil,mostlyoxidised
  decomposed organic matter <1000 Da that has self assembled into large structures
  – Peat - humic material in an aerobic conditions such as swamps, pits, bogs
  – Sapropel - organic matter: phytoplankton, zooplankton, spores, plants, fish, deposited in lakes, lagoons, ocean basins, also under anaerobic conditions
  Humin – not soluble at all - Black

Question 4

How much coal is consumed annually world wide

Answer 4

6.4 billon tones

Question 5

how much coal does China and India use

Answer 5

1.3 billion tonnes

Question 6

How much of the USA electricity comes from coal

Answer 6

50%

Question 7

How much of the world electricity is from coal

Answer 7

40%

Question 8

How much coal is there in the world and how long can supply last

Answer 8

1000 billion tonnes 300 years supply at current consumption

Question 9

How is coal formed

Answer 9

Formed from peat deposits
* Peat formed from vegetation
buried in sediment in river
beds, valleys and basins
* Over time peat deposit is
buried deeply as sediment
builds up
* Peat metamorphosis to coal
due to high pressure and
temperature

Question 10

How much co2 does 1 kg of coal produce

Answer 10

3 kgs

Question 11

what are the 4 different types of coal mining

Answer 11

Open cast mining, if
near surface e.g.
Huntly coal mine
– Room and pillar
(USA)
– Longwall (Australia)
– Highwall

Question 12

Dangers in coal mining

Answer 12

Slope failure (open cast)
– Roof collapse
– Gas explosions
– Chronic lung diseases from inhalation of coal dust

Question 13

Environmental impacts of coal mining

Answer 13

Major disruption of habitat
* Large amounts of earth to shift to access coal seam, so earth shifted to nearby valley or heaped in mounds
Coal can have high sulphur and heavy metal content which leech out of coal and waste mounds during rainfall
* This results in acidification and heavy metal contamination of surrounding soils and water ways

Question 14

what is the calorific value of coal

Answer 14

25–35 MJ/kg