Crude oil provides us with many useful substances, some of them quite obvious like plastics, or the fuels petrol and diesel. There are some, however, that are a little less obvious including bubble gum and lipstick. You need to know about a number of these substances for GCSE Chemistry, and also some of the main processes that they must go through to make them useful.
Crude oil is an important source of the chemicals that are needed to manufacture plastics. It was formed by the anaerobic decay of dead marine plants and animals as the mud on the bottom of the sea gradually turned into rock over a time period of millions of years. Oil is a liquid and can therefore flow through pores and cracks in rock. It is less dense than the surrounding rock and it is under pressure because of the weight of the rocks above so it will rise upwards. If it reaches an impermeable rock layer, it becomes trapped - otherwise it just seeps out at the surface of the Earth. Drilling a hole through the impermeable rock allows us to release the oil trapped underground.
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The chemicals used to make plastics and fuels don't come directly from crude oil - they need to be manufactured. One starting point is the process of thermal catalytic cracking of the larger molecules like those found in the bitumen fraction. Cracking produces a mixture of shorter chain alkanes and alkenes. The alkenes have a double bond and this makes them more reactive than alkanes. They can therefore either be used directly to make plastics or converted into chemicals that can then be used to make plastics.
Plastics are long chain chemicals called polymers. Their chains can be made from the same chemical e.g. ethene is used to make poly(ethene), better known as polythene, or from different chemicals e.g. nylon. Changing the conditions of polymerisation very slightly can greatly alter the nature of the polymer produced e.g the different types of poly(ethene).
Have a go at this quiz and see what you have learned about the fuels, plastics and other substances we get from crude oil.
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1.
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The main products from crude oil are fuels. Which of the following fuel is most likely to be used in an aeroplane? |
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| [ ] |
Butane |
| [ ] |
Diesel |
| [ ] |
Kerosene |
| [ ] |
Petrol |
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|
|
2.
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Which of these fuels is most likely to be used for camping stoves? |
|
| [ ] |
Butane |
| [ ] |
Diesel |
| [ ] |
Kerosene |
| [ ] |
Petrol |
|
|
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3.
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Why does 'light' crude oil cost more than 'heavy' crude oil? |
|
| [ ] |
It is lighter in weight |
| [ ] |
It contains more big molecules |
| [ ] |
It contains more small molecules |
| [ ] |
It is lighter in colour |
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4.
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Methane is the source of hydrogen for... |
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| [ ] |
the Haber process |
| [ ] |
making ethanol |
| [ ] |
producing polymers |
| [ ] |
cracking hydrocarbons |
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5.
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One possible product of cracking hydrocarbons can be ethene. Ethene can be used to manufacture ethanol, which is used as a fuel. What conditions are required for this reaction to take place? |
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| [ ] |
High pressure and catalyst |
| [ ] |
High pressure and high temperature |
| [ ] |
High temperature and catalyst |
| [ ] |
High pressure, high temperature and catalyst |
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6.
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Pick the correct equation to show the production of ethanol from ethene. |
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| [ ] |
C2H4 + H2O → C2H5OH |
| [ ] |
C2H4 + H2O → C2H4OH |
| [ ] |
C2H4 + H2 → C2H5OH |
| [ ] |
C2H6 + H2O → C2H5OH |
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7.
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Ethene can also be used to make poly(ethene). What type of reaction is required for this to occur? |
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| [ ] |
Cracking |
| [ ] |
Thermal decomposition |
| [ ] |
Displacement |
| [ ] |
Polymerisation |
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8.
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When ethene is polymerised, depending on the conditions, slightly different substances are formed. LDPE is formed with very high pressure and a trace of oxygen, whereas HDPE is formed using a catalyst at 50oC and a high pressure. What is the main difference between these two types of poly(ethene)? |
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| [ ] |
LDPE is stronger and has a higher softening temperature than HDPE |
| [ ] |
HDPE is stronger and has a higher softening temperature than LDPE |
| [ ] |
HDPE is stronger and has a lower softening temperature than LDPE |
| [ ] |
LDPE is stronger and has a lower softening temperature than HDPE |
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9.
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Plasticisers are sometimes added to polymers. For what reason? |
|
| [ ] |
To increase a polymer's melting point |
| [ ] |
To make the polymer stronger |
| [ ] |
To make the polymer soluble in water |
| [ ] |
To make the polymer more flexible |
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10.
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Pick the correct combination for uses for plasticised PVC and unplasticised uPVC. |
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| [ ] |
PVC - ropes and carpets
uPVC - carrier bags and water bottles |
| [ ] |
PVC - drain pipes and window frames
uPVC - wire insulation and shrink wrap |
| [ ] |
PVC - wire insulation and shrink wrap
uPVC - drain pipes and window frames |
| [ ] |
PVC - drain pipes and window frames
uPVC - carrier bags and carpets |
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|
1.
|
The main products from crude oil are fuels. Which of the following fuel is most likely to be used in an aeroplane? |
|
| [ ] |
Butane |
| [ ] |
Diesel |
| [x] |
Kerosene |
| [ ] |
Petrol |
|
|
|
2.
|
Which of these fuels is most likely to be used for camping stoves? |
|
| [x] |
Butane |
| [ ] |
Diesel |
| [ ] |
Kerosene |
| [ ] |
Petrol |
|
|
|
3.
|
Why does 'light' crude oil cost more than 'heavy' crude oil? |
|
| [ ] |
It is lighter in weight |
| [ ] |
It contains more big molecules |
| [x] |
It contains more small molecules |
| [ ] |
It is lighter in colour |
|
|
|
4.
|
Methane is the source of hydrogen for... |
|
| [x] |
the Haber process |
| [ ] |
making ethanol |
| [ ] |
producing polymers |
| [ ] |
cracking hydrocarbons |
|
|
|
5.
|
One possible product of cracking hydrocarbons can be ethene. Ethene can be used to manufacture ethanol, which is used as a fuel. What conditions are required for this reaction to take place? |
|
| [ ] |
High pressure and catalyst |
| [ ] |
High pressure and high temperature |
| [ ] |
High temperature and catalyst |
| [x] |
High pressure, high temperature and catalyst |
|
|
|
6.
|
Pick the correct equation to show the production of ethanol from ethene. |
|
| [x] |
C2H4 + H2O → C2H5OH |
| [ ] |
C2H4 + H2O → C2H4OH |
| [ ] |
C2H4 + H2 → C2H5OH |
| [ ] |
C2H6 + H2O → C2H5OH |
|
|
|
7.
|
Ethene can also be used to make poly(ethene). What type of reaction is required for this to occur? |
|
| [ ] |
Cracking |
| [ ] |
Thermal decomposition |
| [ ] |
Displacement |
| [x] |
Polymerisation |
|
|
|
8.
|
When ethene is polymerised, depending on the conditions, slightly different substances are formed. LDPE is formed with very high pressure and a trace of oxygen, whereas HDPE is formed using a catalyst at 50oC and a high pressure. What is the main difference between these two types of poly(ethene)? |
|
| [ ] |
LDPE is stronger and has a higher softening temperature than HDPE |
| [x] |
HDPE is stronger and has a higher softening temperature than LDPE |
| [ ] |
HDPE is stronger and has a lower softening temperature than LDPE |
| [ ] |
LDPE is stronger and has a lower softening temperature than HDPE |
|
|
|
9.
|
Plasticisers are sometimes added to polymers. For what reason? |
|
| [ ] |
To increase a polymer's melting point |
| [ ] |
To make the polymer stronger |
| [ ] |
To make the polymer soluble in water |
| [x] |
To make the polymer more flexible |
|
|
|
10.
|
Pick the correct combination for uses for plasticised PVC and unplasticised uPVC. |
|
| [ ] |
PVC - ropes and carpets
uPVC - carrier bags and water bottles |
| [ ] |
PVC - drain pipes and window frames
uPVC - wire insulation and shrink wrap |
| [x] |
PVC - wire insulation and shrink wrap
uPVC - drain pipes and window frames |
| [ ] |
PVC - drain pipes and window frames
uPVC - carrier bags and carpets |
|
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