1. Crude oil and fractional distillation
Module C1.4
Crude oil and fractional distillation

2. Objectives
Must Recall that crude oil is a mixture of a large number of compounds Should Define the term hydrocarbon Could Explain how the compounds in crude oil can be separated using physical methods including fractional distillation

3. Starter
In your class books leave a gap to stick in your C1.3 booklets.
Write a new titles C1.4 Crude Oil

4. Starter Video about crude oil (BP education)
Watch the video about crude oil and jot down answers to the following:
What is crude oil made of?
What do we use crude oil for?

5. Crude oil
Crude oil is a mixture of a very large number of compounds and is made from the the bodies of plants and animals that have decayed many millions of years ago. A mixture is two or more substances NOT chemically combined together (such as a mixture of sand and water that can be separated by filtration).

6. Hydrocarbons
Most of the compounds in crude oil consist of molecules made up of hydrogen and carbon atoms only.
We call these HYDROCARBONS
We can separate the different unchanged hydrocarbons from crude oil by FRACTIONAL DISTILLATION.

7. Uses of crude oil
Crude oil can be separated using a technique called FRACTIONAL DISTILLATION
Fractional distillation produces products we can use for lots of different applications.
What applications did you come up with?

8. Jet fuel

9. Petrol and diesel

10. Plastics and polymers

11. Fractional distillation
Fractional distillation separates a mixture into a number of different parts, called fractions.
A tall column is fitted above the mixture, with several condensers coming off at different heights.
The column is hot at the bottom and cool at the top. Substances with high boiling points condense at the bottom and substances with low boiling points condense at the top.
Fractional distillation works because the different substances in the mixture have different boiling points.
Click above link for BP Education service videos.

12. Fractional distillation

13. Key points for exam questions
To explain fractional distillation [3 marks]
Heat crude oil to make it a gas/vapour
Cool to condense
Hydrocarbons condense at different temperatures (boiling points).

14. Different hydrocarbon – different BP
Different hydrocarbons have different numbers of carbon atoms.
The higher the number of carbon atoms the higher its boiling point.

15. Key points for exam questions
A fraction is a set of hydrocarbon molecules of similar size and similar boiling points

16. Plenary Now attempt booklet questions Q2(a) and 2(b). Q3 (i) and (iii)
Q5 (a)(i) AND
Q6 (a)(i)

17. C1.4 Crude oil
Lesson 2 - alkanes

18. Objectives
Must
Recall that most of the compounds in crude oil consist of hydrocarbons called alkanes.
Should
Describe the general formula of an alkane and draw the structure.
Could
Explain the naming of alkanes up to a chain length of four carbon atoms.

19. Starter Oil samples Using BP oil samples
Identify low molecular weight (gases), medium molecular weight (liquids) that can be obtained from fractional distillation of crude oil

20. Alkanes
Alkanes are the name of a type of chemical that makes up the compounds in crude oil.
They are hydrocarbons (contain only hydrogen and carbon) and form a series of increasing molecular weight.

21. Hydrocarbons video

22. Carbon chains
Alkanes are chains of carbon atoms with hydrogen atoms attached to them.
There is an alkane with one carbon atom, two carbon atoms, three, four, five and so on. The chains can be massive with hundreds of carbon atoms.
You need be able to name and draw the first four and recognise some larger ones.

23. Methane One carbon atom bonded to four hydrogen atoms.
Each line represents a single covalent bond.

24. Two carbon atoms six hydrogen atoms
Ethane
Two carbon atoms six hydrogen atoms

25. Three carbon atoms eight hydrogen atoms
Propane
Three carbon atoms eight hydrogen atoms

26. Four carbon atoms ten hydrogen atoms
Butane
Four carbon atoms ten hydrogen atoms

27. AfL Now attempt question 2(c) in your booklets.
Then attempt question 6(b) in your booklets
Then attempt question 9 in your booklets

28. CnH2n+2 Can you spot a pattern?
Every time we increase the number of carbons what happens to the number of hydrogens?
We can work out a general formula for any alkane it is:
CnH2n+2
where n is the number of carbon atoms
and 2n+2 is the number of hydrogen atoms

29. Counting in chemistry
Rather than the numbers 1,2,3 and 4 when we are counting in chemistry we use the terms:
meth_ = 1
eth_ = 2
prop_ = 3
but_ = 4
The first four alkanes are therefore called methane, ethane, propane and butane.

30. Lesson 3 – properties of hydrocarbons
C1.4 Crude Oil
Lesson 3 – properties of hydrocarbons

31. Objectives
Must recall the term alkane and the names for the first four alkanes in the series. State that these substances are commonly used as fuels. Should describe the difference between a saturated and an unsaturated hydrocarbon Could explain the boiling points, flammability and viscosity of hydrocarbon fuels.

32. Starter - Quiz What is the name of the alkane with the formula CH4
What is the name of this alkane?
Draw a molecule of propane showing all the bonds.

33. Starter - Quiz
What is the name of the alkane with the formula CH4 - methane
What is the name of this alkane? ethane
Draw a molecule of propane showing all the bonds.

34. Spot the difference

35. Spot the difference Ethane Ethene All single bonds Full of hydrogen
Saturated
Has double bond
Fewer hydrogens
Unsaturated

36. Properties
Some properties of hydrocarbons depend on the size of their molecules.
These properties influence how hydrocarbons are used as fuels.
Identify solids, liquids and gases in the following images…

37. Liquid or gaseous fuels

38. Liquid/Gas
For this list of substance state whether liquid or gas at room temperature?
Hydrocarbon
Boiling point in °C
Solid/Liquid/Gas
methane, CH4
-162
butane, C4H10
pentane, C5H12
+36
decane, C10H22
+175

39. Viscosity – new keyword
This simply means thickness of solution.
For example water has a lower viscosity than treacle
Generally the higher the molecular weight (longer carbon chain) the more viscous the substance is.
Bitumen has very long chain molecules and is very viscous and stick (tar).

40. Plenary - AfL
Attempt question 1(a)
Attempt question 8(a)

41. Lesson 4 – hydrocarbon fuels
C1.4 Crude oil
Lesson 4 – hydrocarbon fuels

42. Objectives
Recall that most fuels contain carbon and/or hydrogen and may contain sulphur.
Describe how, when a fuel burns gases are released into the atmosphere.
Explain how the combustion of a fuel releases energy.

43. Starter
Using your whiteboards list as many hydrocarbon fuels as you can.
Think back to the diagram of fractional distillation of crude oil. What examples can you remember?

44. Did you get? Methane Propane Butane Petrol Diesel Kerosene Fuel oil
+ many more

45. Burning fuels releases energy!

46. Combustion
Complete combustion occurs when there is enough oxygen – for example when the hole is open on a Bunsen burner.
The products of complete combustion are carbon dioxide and water.
CH4 + 2O2  CO2 + 2H2O

47. AfL - Complete combustion

48. Incomplete combustion
Incomplete combustion occurs when there is not enough oxygen – for example when the hole is closed on a Bunsen burner.
The products of incomplete combustion include carbon monoxide and carbon (soot). It is often called a sooty flame.

49. AfL – incomplete combustion

50. Carbon dioxide Carbon dioxide is a greenhouse gas.
This means it causes global warming by trapping heat from the sun within the Earth’s atmosphere.

51. Carbon monoxide
Carbon monoxide is an odourless and tasteless poisonous gas.
If produced in an enclosed space it can be deadly.

52. Soot/smoke particles
Particles of carbon from incomplete combustion can be released into the atmosphere.
This contributes to GLOBAL DIMMING

53. Other pollutants
Sulphur present in fuels burns to produce sulphur dioxide.
At high temperatures oxides of nitrogen may also be formed from nitrogen in the atmosphere.
These react with water in the atmosphere to form ACID RAIN

54. Acid rain

55. Cleaning up
Undesirable combustion products can be cleaned from emissions before they leave the chimney by using a filter or catalytic converter (cars).

56. Exam question 1d

57. Exam question 7c

58. Exam question 10

59. Exam question 10

60. Homework
Now complete questions 11, 12 and 13 for homework.

61. C1.4 Crude Oil
Lesson 5 - Biofuels

62. Objectives Recall that biofuels are produced from plant material
Describe the fuels that can be produced from plant material
Evaluate the advantages and disadvantages of making fuel from renewable sources.

63. Starter
Can you recall some of the uses of crude oil?

64. The problem with crude
Crude oil is a limited resource that will eventually run out.
Alternatives are needed and some are already under development.

65. Alternative fuels

66. Ethical and environmental issues
The video described some potential issues with biofuels.
Can you describe any?

67. Ethical and environmental issues
Clearance of rainforests to plant fuel crops
Using land formerly used for food crop (causing hardship)
Not replacing crops with sufficient crops after harvest for the process to remain carbon neutral
Erosion – replacing trees with crops with shallow roots

68. Carbon neutral
Plants photosynthesise using carbon (dioxide) from the air
Biodiesel/biothanol releases carbon (dioxide) from plants
Plants are replanted and photosynthesise, removing the carbon (dioxide) again.
(fossil) diesel from crude oil releases ‘locked up’ carbon (dioxide) and doesn’t absorb any CO2

69. Different types of biofuels
Ethanol – produced by fermentation of sugars in sugarcane
Biodiesel – produced from hydrolysis of vegetable oils

70. Examination question Q14 (b)

71. Examination question Q14(b)

72. Mark scheme

73. Past paper question.

74. Mark scheme