1. Learning objectives Introduce hydrocarbons, alkanes and the IUPAC nomenclature for alkanes and alkyl groups. To understand the concept of isomers.

2. Hydrocarbons The simplest organic chemicals What elements do you think they contain?

3. Bonds How many bonds can a Carbon atom make?How many bonds can a Hydrogen atom makeWhat will the formula be for the simplest hydrocarbon?What is it called? Carbon can form single, double and triple bonds with other carbon atoms so starting to build chains

4. Alkanes These are the simplest family of hydrocarbonsAll carbons linked by single C-C bondsWidely used as fuelsObtained by fractional distillation of crude oil They are one of three families of hydrocarbons known as Aliphatic hydrocarbons – all of which only contain 2 elements.

5. Alkanes  Methane  Ethane  Propane  Butane  Pentane  Hexane  Heptane  Octane  Nonane  Decane  And so on  CH 4  C 2 H 6  C 3 H 8  C 4 H 10  Work out the empirical formula NameFormula

6. Bigger Alkanes  11  12  13  14  15  20  21  22  30  31  40  50  100  Undecane  Dodecane  Tridecane  Tetradecane  Pentadecane  Icosane  Henicosane  Docosane  Triacontane  Hentriacontane  Tetracontane  Pentacontane  Hectane No. of carbonsname What would be the names of straight chain alkanes containing 33 and 47 carbons?

7. Isomers Butane upwards have isomers Methane, ethane and propane do not have isomers Isomers may have different properties These molecules of the same formula but different shape are called isomers. As the chains get longer there are more ways that they can be put together.

8. Butane isomers

9. The number of possible isomers increases with chain length  Butane (4)  Pentane (5)  Hexane (6)  Heptane (7)  Octane (8)  Nonane (9)  Decane (10)  Pentadecane (15)  Icosane (20)  Tetracontane (40)  2  3  5  9  18  35  75  4347  366 319  62 491 178 805 831 Name and (no. of carbons)Number of possible isomers

10. Naming isomers A nightmareEasy with pentane C5H12 which has 3 isomersStraight chain is n-pentane1 methyl side branch is isopentane2 methyl side branches is NeopentaneDraw these so you are clear what we are talking aboutAfter this it stops

11. Types of formulae  There are four ways of showing formulae of organic compounds  Look at these examples for decane  1. Molecular formulae: C 10 H 22  2. Condensed structural formulae:  CH 3 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 3  3. Structural formulae  4. Line structure:

12. Applying the IUPAC rules 1 Pick out the longest continuous branch and name it thus.2 Identify the substituent groups attached to the parent chain and name them 3 Number the chain in the direction that gives the lower number to the first substituent group 4 Write the name of the compound starting with the number of the first substituent and then its name followed by any other substituents’ – number and name 5 name substituents in alphabetical order. E.g. 3 ethyl 2 methyl heptane6. Use prefixes di, tri etc. to indicate 2, three or more of the same substituent

13. Alkyl groups These are what we call the side chains. They have one less hydrogen than the alkane with the same number of carbons E.g. Methane has CH4As a side chain it has CH3 and is known as a methyl group. To name alkyl groups simply drop the ending ane and add yl and remove one hydrogen from the formula.

14. Other side groups You can have halogensCl – chlorine becomes chloroBr – Bromine becomes bromoI – Iodine become iodoF – fluorine becomes fluoro Other options include aromatics – see later lessons and metals such as Iron, copper etc.

15. Plenary Draw or use the models to make:Hexane2 methyl pentane2,3, methyl heptane4 ethyl nonane2chloro butane1chloro 3 methyl hexaneName the six molecules the teacher has drawn on the board.

16. Themes for investigating: Aliphatic Hydrocarbons 1 How do physical and chemical properties change with increased chain length? 2. What are the chemical properties of double and triple carbon-carbon bonds? 3. How do we name alkanes, alkenes and alkynes? 4. What are the main uses of alkanes, alkenes and alkyne?s 5. What are the cycloaliphatics and how are their properties different from straight chain hydrocarbons?

17. Product of investigation-  1. Each of you will form a new group to share what you have learnt and this you will show on a poster.  2. Each group will develop an activity to help reinforce learning with the whole class.  3. Each group will provide a presentation to give to the whole class  4. The class will complete 5 exercises based on these five themes.  5. Members of each group will be responible for helping students to clarify any further doubts once the marked work is returned to them.

18. Rubric MarksPoster (individual) The part you contributed Presentation (team) Investigation (individual) Learning activity (group) Clarification of doubts. Individual 2 very weakVery muddledNever on taskNo helpcannot 4Some key pointsSomre areas understandabl e Mostly on task but rated poorly by captain Could help but very boring Has some idea 6Mostly thereMost of information correctly included Good rating by captain Good but not much fun Basically correct but questioner remains confused 8Fully coveredComprehensiv e and correct Fully on task excellent rating by captain Good and interesting Helps