1. Sources of Hydrocarbons

2. Hydrocarbons
Hydrocarbons are compounds consisting of hydrogen and carbon only, bonded together covalently.

3. Sources
Fossil Fuels
Crude Oil
Natural gas
Coal

4. Crude oil and natural gas were formed from the remains of marine plants and animals.
Coal was produced from dead wood

5. Hydrocarbons
CH4
Methane

6. Methane Production Methane can be produced in: Coalmines Slurry pits
Waste dumps
Digestive tracts of animals

7. Hazards of Methane Production
Fires and explosions
Death by suffocation
Contributes to the greenhouse effect

8. When the chain is between 5 and 9 carbons, the hydrocarbon is gasoline
When the chain is between 5 and 9 carbons, the hydrocarbon is gasoline. About a dozen carbons and it is diesel. Around 20 carbons is motor oil. A chain of hundreds to thousands of carbon and hydrogens make plastic. This particular plastic is polyethylene.

9. Petroleum distillation

14. Carbon groups Alkanes CnH2n+2 Methane CH4 GAS Ethane C2H6 GAS
Propane C3H GAS
Butane C4H GAS
Pentane C5H LIQUID
Hexane C6H LIQUID

16. Naming carbon groups Methyl CH3 Ethyl C2H5 Propyl C3H7 Butyl C4H9
Pentyl C5H11

17. Alkanes
Hydrocarbon chains where all the bonds between carbons are SINGLE bonds
Name uses the ending –ane
Examples: Methane, Propane, Butane, Octane, 2-methylpentane

18. Step 1. Find the parent chain.
Where is the longest continuous chain of carbons?

19. Step 2. Number the parent chain.
Number the parent chain so that the attached groups are on the lowest numbers
Methyl is on carbon #2 of the parent chain
Methyl is on carbon #4 of the parent chain
GREEN is the right way for this one! 2 7 1
Groups on 2 and 5
Groups on 4, 6, and 7
Groups on 2, 3, and 5
Groups on 3 and 6

20. Step 3. Name the attached groups.
Carbon (alkyl) groups
Methyl CH3 -
Ethyl CH3CH2-
Propyl CH3CH2CH2 –
Halogens
Fluoro (F-)
Chloro (Cl-)
Bromo (Br-)
Iodo (I-)

21. Step 4. Designate where the group is attached to the parent chain.
Use the numbers of the parent chain from step 2 to designate the location of the attached groups to the parent chain.
2-methyl

22. Step 5. Alphabetize the groups, combine like groups, and assemble.
The prefixes di, tri, tetra etc., used to designate several groups of the same kind
Prefixes are not considered when alphabetizing (Example: dimethyl = m for alphabetizing)
Parent chain goes LAST
1,1,1-trichloro-1-fluoromethane
1,1-dichloro-1,1-difluoromethane

23. Draw Some Simple Alkanes
2-methylpentane
3-ethylhexane
2,2-dimethylbutane
2,3-dimethylbutane

26. Alkenes
CnH2n-2
Ethene
Propene
Butene
Pentene
Hexene

29. Alkenes

33. Preparation and properties of Ethene gas
Aluminium oxide(CATALYST) removes a water molecule from ethanol and produces ethene gas

34. Preparation of ethene

35. Practical precautions of ethene
Avoid suck back by removing heat before dismantling the equipment
Discard first gas jar as it will have a mix of air and ethene

36. Precautions
Why is it desirable to push the glass wool into the tube after the ethanol has been added?
To ensure that all of the ethanol is soaked up.
Why should the ethanol not be heated strongly?
Strong heating of the ethanol will cause it to evaporate too quickly and escape from the tube before it can be dehydrated.

37. Combustion C₂h₄ + 3O₂ → 2CO₂ + 2H₂o Lime water test
PHYSICAL PROPERTIES: It is a colourless gas with a sweetish smell. It is insoluble in water so you can collect it over water.
Combustion C₂h₄ + 3O₂ → 2CO₂ + 2H₂o Lime water test

42. Ethyne preparation

43. Preparation of ethyne The first test tube should be discarded.
Add small amounts of calcium carbide as it is very reactive with water

71. The preparation of ethanal

72. Preparation of ethanal
Why is it necessary to turn off the Bunsen burner or heating element before the reaction is started?
The reaction would become too vigorous, and some unreacted ethanol and other material is likely to be forced over into the conical flask. Once the mixture in the reaction vessel has been brought to the boil, further heating is not required as the oxidation of ethanol is an exothermic reaction, and gentle boiling can be maintained by regulating the flow from the dropping funnel.

73. TOLLENS REAGENT TEST FOR ALDEHYDES

75. Aldehydes and ketones behave differently.
You will remember that the difference between an aldehyde and a ketone is the presence of a hydrogen atom attached to the carbon-oxygen double bond in the aldehyde. Ketones don't have that hydrogen.
Fehlings test is used to distinguish the diffference in functional groups.

86. Preparation of Ethanoic acid
Reflux (20 mins)
Mix 2 cm3 of ethanol and
10 cm3 of deionised water in the dropping funnel.
5g of sodium dichromate
5cm3 of sulphuric acid
Cool flask with tap water

87. Preparation of ethanoic acid
Mix 2 cm3 of ethanol and 10 cm3 of deionised water in the dropping funnel.
2.Add the solution from the dropping funnel dropwise down the condenser, while swirling the contents of the flask and cooling it if necessary to prevent too vigorous a reaction.

88. Cool the apparatus, dismantle and rearrange for distillation

89. Summary of practical setup of ethanoic acid

90. Precautions
Reflux distillation involves condensing the vapour from a boiling liquid in such a way as to return the condensed material to the reaction vessel.
In this way a reaction may be carried out at quite a high temperature while preventing the loss of any of the reactants or products.