Organic Chemistry

1. Organic Chemistry 1234 bonds Topic 10.1.1 – 10.1.8 HONC

2. What is organic chemistry? • study of carbon, the compounds it makes, and the reactions it undergoes • over 16 million carbon-containing compounds are known • because the C-C single bond (348 kJ mol-1) and the C-H bond (412 kJ mol-1) are strong, carbon compounds are stable • carbon can form chains and rings

3. Homologous series/compounds (10.1.1) • related compounds that have the same functional group (groups of atoms found within molecules that are involved in the chemical reactions characteristic of those molecules)

5. differ from each other by a CH2 unit • can be represented by a general formula • examples: • CnH2n+2 (alkanes) or CnH2n (alkenes) or…

7. have similar chemical properties • have physical properties that vary in a regular manner as the number of carbon atoms increases • Example: the alkanes

9. Trends in boiling points of members of a homologous series (10.1.2) • melting point and boiling point increase with more carbon atoms • Why? • intermolecular forces increase • adding a CH2 adds more electrons • this increases the Van der Waal’s forces

11. Empirical, molecular & structural formulas (10.1.3)

12. empirical formula • simplest ratio of atoms in a molecule • molecular formula • actual numbers of atoms in a molecule

13. structural formula • unambiguously shows how the atoms are bonded together • can use condensedstructural formulas • bonds are omitted, repeated groups put together, side chains put in brackets • CH3CH2CH2CH2CH2CH3 • or even CH3(CH2)4CH3 • CH3CH(CH3)CH3

14. condensed

15. skeletal formula • not accepted in the IB for answers but often used in questions • every “corner” represents a carbon • hydrogens are implied

16. Isomers (10.1.4) • (structural) isomers: compounds with the same molecular formula but different structure (arrangement of atoms)

17. different isomers are completely different compounds • have different physical properties such as melting point and boiling point

18. Structural Formulas for C4H10O Isomers

19. Structural formulas for the isomers of non-cyclic alkanesup to C6(10.1.5) Alkanes • hydrocarbon chains where all the bonds between carbons are SINGLE bonds • CnH2n+2 • draw out and write the structural formulas for all isomers that can be formed by: • CH4 • C2H6 • C3H8 • C4H10 • C5H12 • C6H14 Richard Thornley 10.1.5 2:54

20. Monkeys Eat Peeled Bananas Naming the isomers (IUPAC) of non-cyclic alkanes up to C6(10.1.6) • Richard Thornley 3:35 • Determine the longest carbon chain • Use the prefix to denote the number carbons

21. use the suffix “-ane” to indicate that the substance is an alkane • number the carbons in the chain consecutively, starting at the end closest to a substituent (groups attached to the main chain/most busy end)

22. name and number the location of each substituent • the name of the substituent will be written before the main chain and will end with “–yl” (or just memorize the below) • CH3 is methyl • C2H5 is ethyl • C3H7 is propyl And with 2 or more side chains: • use prefixes di-, tri-, tetra-, to indicate when there are multiple side chains of the same type • use commas to separate numbers and hyphens to separate numbers or letters. • name the side chains in alphabetical order

23. How about C5H12? The isomers are: Pentane 2-methyl-butane 2,2-dimethyl propane

24. Nomenclature Practice Name this compound Step #1: For a branched hydrocarbon, the longest continuous chain of carbon atoms gives the root name for the hydrocarbon 1 9 carbons = nonane 2 4 3 5 6 7 8 9

25. Nomenclature Practice Name this compound 9 carbons = nonane 1 2 4 3 5 6 CH3 = methyl 7 chlorine = chloro 8 9 Step #2: When alkane groups appear as substituents, they are named by dropping the -ane and adding -yl.

26. Nomenclature Practice Name this compound Step #3: The positions of substituent groups are specified by numbering the longest chain of carbon atoms sequentially, starting at the end closest to the branching. 9 carbons = nonane 1 2 4 3 5 6 CH3 = methyl 7 chlorine = chloro 8 9 1 9 NOT 9 1

27. Nomenclature Practice Name this compound Step #4: The location and name of each substituent are followed by the root alkane name. The substituents are listed in alphabetical order (irrespective of any prefix), and the prefixes di-, tri-, etc. are used to indicate multiple identical substituents. 9 carbons = nonane 1 2 4 3 5 6 CH3 = methyl 7 chlorine = chloro 8 9 2-chloro-3,6-dimethylnonane

28. Alkenes Structural formulas for the isomers of the straight chain alkenesup to C6(10.1.7) • alkenes have a double bond between two or more of the carbons • CnH2n • draw out and write the structural formulas for all isomers that can be formed by each • C2H4 • C3H6 • C4H8 • C5H10 • C6H12 Richard Thornley 10.1.7 (1:37)

29. Naming the isomers (IUPAC) of straight chain alkenes up to C6(10.1.8) • suffix changes to “-ene” • when there are 4 or more carbon atoms in a chain, the location of the double bond is indicated by a number • begin counting the carbons closest to the end with the C=C bond • numbering the location of the double bond(s) takes precedence over the location of any substituents 1-butene 2-butene but-1-ene but-2-ene

30. Naming Practice!!! choose the correct ending ene

31. determine the longest carbon chain with the double bond ene

32. assign numbers to each carbon ene

33. assign numbers to each carbon ene

34. attach prefix (according to # of carbons) ene 1-hexene

35. ethyl methyl methyl determine name for side chains 1-hexene 1-hexene

36. ethyl methyl methyl attach name of branches alphabetically 2-ethyl-4-methyl-4-methyl-1-hexene

37. ethyl methyl methyl group similar branches 2-ethyl-4-methyl-4-methyl-1-hexene

38. ethyl methyl methyl group similar branches 2-ethyl-4,4-dimethyl-1-hexene or 2-ethyl-4,4-dimethyl hex-1-ene

39. propene 2,4-dimethyl-2-pentene 2,4-dimethyl pent-2-tene 2-butene

40. a) 3,3-dimethyl-1-pentene b) same C H 3 C H C C C H C H C H 3 3 C H 3 c) 4,5 dimethyl-2-hexene