1. Carbon Chemistry

2. Carbon: Random facts Carbon occurs in all living organisms.
It can take the form of one of the hardest substances (diamond) or one of the softest (graphite).
Carbon is made in the interiors of stars, though it was not produced in the Big Bang.
9.5% of our body is made up of carbon

3. Why does carbon form so many compounds?
Each carbon has 4 valence electrons
each valence electron is available to form one bond with other atoms
Carbon can form strong covalent bonds with other carbon atoms
Bonds between carbon atoms can be single or multiple (e.g. double or triple)

4. Hydrocarbons Compounds that consist of hydrogen and oxygen only
Coal, oil and natural gas are sources of hydrocarbons
They are classed into families:
Alkanes
Alkenes
Alkyns
Cycloalkanes

5. Hydrocarbon prefixes No of carbons Prefix 1 Meth- 2 Eth- 3 Prop- 4
But- 5
Pent- 6
Hex- 7
Hept- 8
Oct- 9
Non- 10
Dec-
Hydrocarbon prefixes
The prefix in the name of a hydrocarbon indicates the number of carbons in each molecule of that hydrocarbon.

6. Homologous series
A series of compounds where each consecutive compound differs by CH2
The members of a homologous series have similar chemical properties
Examples: alkanes, alkenes etc.

7. Alkanes Contain SINGLE bonds only i.e.
each carbon forms a single covalent bond to 4 other atoms
each hydrogen forms a single covalent bond to one carbon atom
General molecular formula: CnH2n+2
Where n is the number of carbons in the molecule
Suffix (end of the name): “–ane”
Saturated hydrocarbons – only having single bonds means that they are “saturated” with hydrogens.
Examples: methane, Heptane, Butane, crude oil contains a variety of alkanes

8. Alkanes: structure
The four atoms bonded to each carbon atom are arranged in a tetrahedral manner around the carbon.
Sometimes there are more than 1 possible arrangement of the atoms which results in different structures.
E.g. Butane
Straight chain
Branched chain
Structural Isomers

9. Alkanes Structure: Have a go!
Draw all of the possible structures for pentane

10. Structural isomers
Molecules with the same molecular formula but different structural formulas (arrangement of their atoms)
Have similar chemical properties but differ in some physical properties (eg melting and boiling point)

11. Alkenes Contain one DOUBLE bond between 2 carbons i.e.
General molecular formula: CnH2n
Where n is the number of carbons in the molecule
Suffix (end of the name): “–ene”
Unsaturated hydrocarbons – the double bond means that they contain less than the maximum no of hydrogens
Examples: Ethene, Octene, Pentene

12. Branches are called alkyl groups
Alkenes: structure
Sometimes there are more than 1 possible arrangement of the atoms which results in different structures. NB: the double bond can also be rearranged
E.g. Butene
Branched chain
Straight chain
Branches are called alkyl groups
Structural Isomers

13. Alkenes structure: Have a go!
Draw all of the possible structures for pentene

14. Semi-structural formulas
The carbon atoms and their attached hydrogen atoms are listed in the order in which they appear in the structural formula
Single bonds aren’t indicated but double bonds are indicated by =
Groups of atoms that form branches are written in brackets after the carbon atom to which they are attached.
E.g. methylpropane
Semi-structural formula: CH3CH(CH3)CH3

15. Semi-structural formulas: Have a go!

16. Questions
P141 Q 4,5 & 6
You have 4 minutes…GO

17. Naming Carbon Compounds
There is a international naming system for hydrocarbons: IUPAC
These are a set of rules that can be followed so that everyone gives a given compound the same name!

18. Naming Carbon Compounds
Identify the longest chain in the structure
Number the carbon atoms in the longest chain, starting at the end that will give the atoms in the double bond the lowest numbers possible
Indicate where the double bond is located by including the carbon number of the first carbon that is involved in the double bond
e.g. But-2-ene indicates that the double bond is between carbons 2 and 3 of the longest chain.

19. Naming Carbon Compounds
4. Alkyl groups (branches) have the prefix of the number of carbons that they contain, and the suffix “-yl”
E.g. a branch containing 1 carbon is a methyl group.
The name of the alkyl group goes in front of the name for the longest chain.
The number of the carbon in the longest chain off which the alkyl group is attached goes in font of the alkyl group name.
E.g. 2-methylpropane

20. Naming: Have a Go!
Name this hydrocarbon:

21. Questions
P147 Q 7 & 8
P162 Q 17, 18, 19, 21, 23, 24, 38, 40

22. Physical Properties of Hydrocarbons
Volatility (ability of liquids to evaporate): Smaller compounds are more volatile than larger compounds
Because less energy is needed to overcome the forces between smaller molecules
Viscosity (thickness of a fluid): smaller compounds have lower viscosity (flow more freely) than larger compounds.

23. Physical Properties of Hydrocarbons
Boiling temperature: increases as molecules get larger.
Viscosity (thickness of a fluid): smaller compounds have lower viscosity (flow more freely) than larger compounds.