Organic Chemistry

1. Organic Chemistry 10 Chemistry

2. Quiz

3. General Formula Description Combustion Reactivity Chemical test Uses CnH2n+2 Saturated Burns in Oxygen to form CO2 + H20 (CO with low O2) Low None Fuels Alkanes

5. The chlorination of methane • Halogenation is the replacement of one or more hydrogens in an organic compound by halogen atoms • When methane is reacted with chlorine the products of the reaction depend on whether there is an excess of methane or chlorine • If there is an excess of methane it form chloromethane and hydrogen chloride

6. To do • Write down a word equation for the chlorination of methane • Can you write a chemical equation? • How about a full balanced chemical equation? Movie

7. Halogenation With an excess of chlorine a mixture of products is formed. Chlorine can obviously replace up to 4 of the hydrogen atoms.

8. Why halogenation? • These products are generally used as intermediate compound for further synthesis

9. Natural Gas and Oil

10. Separating the fractions

11. Fractional distillation • Preheated crude oil is pumped into the column (340 C) • The vapour in the crude oil rises due to differences in density with different fractions condensing in different regions • The liquid part of the crude oil sinks in the column • The low density fractions are thin and light coloured, the high density fractions are ‘viscous’ and dark

12. diesel oil bitumen

13. How does it work? • Components separate due to different boiling points • Crude oil is a mixture of hydrocarbons • Molecules are chemically bonded with strong covalent bonds but contain different numbers of carbon atoms

15. Go on… • The weak attractive forces between the molecules have to be broken if the hydrocarbon is to boil • The longer the hydrocarbon molecule is, the stronger the intermolecular forces are • The shorter chains are more volatile – they form a vapour

16. Boiling

17. Volatility • We can smell petrol (gasoline) much easier than we can smell engine oil • This is because petrol has 5-10 carbon atoms and engine oil has 14-20 carbons atoms

18. Combustion combustion

19. Viscosity Viscosity

20. http://www.rsc-oilstrike.org/preloader.swf

21. Homework • Go to: http://www.rsc-oilstrike.org/preloader.swf • Play the game • Take a screen shot (print screen) or use the snipping tool to take an A4 image • Print this out and stick it in • Winner (most money) gets a ‘get out of homework free’ card

22. Incomplete Combustion

23. Alkanes

24. The end of year test • Can contain ANYTHING we have covered over the course of this year (see specific learning objectives) • May contain anything from the Organic Chemistry too

25. Youtube Origami time You only get one chance

33. Homologous series • A family of hydrocarbons is a homologous series • This means they have the same functional groups • You can have alcohols (ROH), alkanes (R-H), Haloalkanes (RX) and MANY OTHERS Roger Frost

34. Isomerism • Hydrocarbons are based upon the number of carbon atoms • The carbon atoms can be rearranged in different ways: these are called isomers 2-methylpropane

37. Alkenes

38. Alkenes • Formed from cracking • One or more double carbon bond • Hence unsaturated • Reactivity due to double bond • Tested with bromine water

40. ethene bromine 1,2-dibromoethane colourless gas brown liquid Colourless liquid

41. Alkenes Temperature / C -104 -48 -6

42. General Formula Description Combustion Reactivity Chemical test Uses CnH2n unsaturated Burns in Oxygen to form CO2 + H20 (CO with low O2) High (double bond), undergo addition reactions Turns bromine water from brown to colourless Making polymers Alkenes

43. Equilateral Triangle

44. Isomers of Alkenes but-1-ene but-2-ene

45. Questions • Q1 (a) Draw displayed formulae for hexene • (b) Describe a test to distinguish between hexane and hexene • Q2 Draw two isomers of pentene • Homework: revise

46. Next lesson • Oil spill clean up