Hydrocarbons

Question 1

What do Hydrocarbon molecules consist of?

Answer 1

A compound that contains hydrogen (H) and carbon (C) only.

Question 2

Give at least 5 examples of Hydrocarbons

Answer 2

Methane
Ethane
Propane
Butane
Octane (petrol)
Diesel
Jet Fuel
Bitumen (used on roads)
Engine Oil
Vegetable Oil
Animal Fat

Question 3

What are fossil fuels? Give some examples.

Answer 3

Many hydrocarbons are fossil fuels. These come from the remains of living things that died millions of years ago.

They are non-renewable and finite.

Examples are: coal, crude oil, natural gas

Question 4

Describe how coal was formed.

Answer 4

Coal was formed from dead trees and other plant material.

• Coal was formed about 300 million years ago when the earth was covered by swampy forests.
• Layer upon layer of these plants died and were compressed and then covered with soil.
• As the layers were successively covered their access to the air was limited and this stopped the full decomposition process creating peat.
• Over the years heat and pressure worked to force out oxygen and hydrogen, leaving carbon-rich deposits, called coal, in layers known as seams.

Question 5

How was crude oil formed?

Answer 5

Crude oil and gas were formed from dead marine organisms

Millions of years ago, huge numbers of microscopic animals and plants - plankton - died and fell to the bottom of the sea. Their remains were covered by mud.

As the mud sediment was buried by more sediment, it started to change into rock as the temperature and pressure increased. The plant and animal remains were altered chemically by this process, and slowly changed into crude oil and natural gas.

Question 6

What is the difference between monomers and polymers? Give examples

Answer 6

• Monomer is a single molecule. ethene; vinyl chloride; ester; styrene
• Polymer is a collection of a large number of molecules e.g. polythene; polyvinyl; polychloride; polyester; polystyrene

Question 7

Are plastics monomers or polymers?

Answer 7

All plastics are polymers

Question 8

What are the negatives of plastics?

Answer 8

They are not bio-degradable.

They get into the oceans and can kill the sea-life and birds.

Question 9

What should be done to counteract the negatives of plastics?

Answer 9

Reduce usage

Recycle

Manufacturers need to come up with alternatives

Question 10

What is the definition of a fuel?

Answer 10

A fuel is something which can be burned to release energy.

Question 11

Name 5 fuels

Answer 11

1. Oil
2. Coal
3. Wood
4. Paper
5. Petrol
6. Diesel
7. Alcohol
8. Gas
9. Dried food

Question 12

What is combustion? Name the two types.

Answer 12

Combustion is another name for burning.

1. Complete combustion
2. Incomplete combustion

Question 13

Explain complete combustion

Answer 13

Burning in a plentiful supply of oxygen or air.

Complete combustion of a hydrocarbon produces water vapour and carbon dioxide.

Question 14

Explain incomplete combustion

Answer 14

Burning when there is a limited supply of air or oxygen.

Incomplete combustion of a hydrocarbon produces particles of carbon (soot), carbon monoxide, as well as water vapour.