C1.22a How crude oil is formed You do not need to remember the details on this sheet for your exam, but you could be asked to apply your knowledge to unfamiliar situations. Crude oil is formed from the remains of microscopic plants and animals that once lived in the sea. When these organisms died, they fell to the sea floor and became buried by sediments. The sediments kept oxygen away and stopped the remains decaying. As more sediments were deposited, the pressure increased and chemical reactions gradually turned the remains into oil. The oil rose up through permeable rocks (rocks with tiny, connected spaces between the grains) until it became trapped by an impermeable layer. This process takes millions of years. 1
Cut out the diagrams and label boxes.
2
Use the ‘Labels’ boxes to label the diagrams.
3
Put the labelled diagrams in the correct order to show how oil is formed and extracted.
4
Arrange the sentence halves in the correct order to explain how crude oil is formed.
A
B
C
D
Labels microscopic sea creatures
impermeable sedimentary rocks
remains of plants and animals buried in sediments
oil
chemical reactions change remains into oil
oil rig
permeable sedimentary rocks
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Sheet 1 of 2
C1.22a How crude oil is formed (cont.) Sentence beginnings Chemical reactions … It takes millions of years … Layers of sediment build up … Microscopic plants in the sea … Oil rises through permeable rocks … The plants and animals die … They become buried in sediments … Tiny animals in the sea … We are using oil much faster than it can be formed …
Sentence endings … and most fall to the sea floor. … eat the plants. … for oil to form. … increasing the pressure on the layers below. … obtain energy for photosynthesis from the Sun. … slowly change the remains of dead organisms into oil. … so oil is a non-renewable fuel. … until it comes to a layer of impermeable rock. … which keep oxygen away and stop them decaying.
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Sheet 2 of 2
C1.22b Crude oil questions Name
Class
Date
Some of these statements are correct, and some are not. Say if each one is correct. If you think a statement is incorrect, write out a corrected version. 1
Crude oil is found in igneous rocks. __________________________________________________________________________________
2
Oil is called a 'fossil fuel' because it is made from the remains of microscopic sea animals and plants that lived millions of years ago. __________________________________________________________________________________
3
The energy stored in oil originally came from the Sun. __________________________________________________________________________________
4
Hydrocarbon molecules always contain hydrogen, carbon and oxygen atoms. __________________________________________________________________________________
5
Crude oil is a mixture of different compounds. __________________________________________________________________________________
6
A hydrocarbon molecule is a mixture of carbon and hydrogen atoms. __________________________________________________________________________________
7
The hydrocarbon molecules in crude oil all have the same number of carbon atoms in their molecules. __________________________________________________________________________________
8
Crude oil is being formed somewhere in the world right now. __________________________________________________________________________________
9
Crude oil is a renewable resource. __________________________________________________________________________________
10 Crude oil contains only hydrocarbon molecules. __________________________________________________________________________________
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C1.22c Oil and profits You do not need to remember the details on this sheet for your exam, but you could be asked to apply your knowledge to unfamiliar situations. We all use fossil fuels in some way – even if only using electricity that has been generated in power stations burning coal or natural gas. However, the energy companies that supply oil and natural gas are in business to make a profit – not just to helpfully supply energy resources! Oil reserves are defined as the oil that can be recovered for a profit, using today’s technology and oil prices. The amount of oil reserves may change if the price of oil goes up or down, or new technology is invented. Oil companies have to make a profit. ‘Profit’ is the difference between the money a company recovers from selling its products, and the money it has to spend to obtain or make these products. The profits depend on the price of oil, which can change for political reasons (for example, if Middle Eastern countries decide to reduce the amount of oil they supply, the price will go up). They also depend on how much it costs to find oil and extract it. The price will go up as all the easily-drilled oil reserves are used up. The graph shows how the price of crude oil has changed since 1990. Suggest some of the things that oil companies need to spend money on to: a find new sources of oil b extract the oil
120
Dollars per Barrel
1
140
c send the oil to customers.
100 80 60 40 20 0
1980
1985
1990
1995
2000
2005
2010
2
Suggest how the costs you mentioned in question 1 are likely to change over time.
3
Does the graph support your answer to question 2? (The dip in 2008 was because of other economic factors not connected with the oil industry.)
4
At present, about 40% of the total crude oil in a particular reserve can be extracted economically. Suggest why this percentage might increase in the future.
5
An oil company has found a new reserve of oil, but is not extracting oil from this source. Suggest why: a they do not extract oil at the moment b they are planning on extracting oil from this source in 10 years' time.
Extra challenge 6
Suggest why the oil reserves with the largest volumes of oil are not necessarily those with the largest amounts of oil that can be extracted profitably.
© Pearson Education 2010. Edexcel GCSE Science Activity Pack This document may have been altered from the original.