1. Organic chemistry Topic 10

2. Organic chemistry Chemistry of carbon compounds
Carbon bonds four times

3. Organic structures [369] Formulas Structures Empirical Molecular Full
Condensed
In between

4. Shape of carbon compounds [369]
Alkane - tetrahedral shape
Alkene – trigonal planar
Alkyne - linear
Lines – in plane of paper
Dash – behind plane of paper
wedge – out of plane of paper

5. Organic nomenclature [370-374]
1) identify longest chain of carbon atoms
2) identify any functional groups
3) identify side chains
Listed in alphabetical order
Use of prefixes di, tri, tetra

6. Organic nomenclature [370-374]
Number of carbons determine “stem” name
See table page 370

7. Organic nomenclature [370-374]
Functional groups are the “suffix” of the name
See table page 371

8. Organic nomenclature [370-374]
Side chains are the “prefix” of the name
See table page 373

9. Exercises 1-4 pages

10. Structural Isomers [375-378]
Compounds with same formula but different structure

11. Structural Isomers [375-378]
Need to know structures and names of all isomers up to C6

12. Structural Isomers [375-378]
Another type of structural isomer is positional isomer

13. homologous series [ ]
Successive compounds that differ by the addition of a CH2 (methylene) group
CH4, C2H6, C3H8, …CnH2n+2
Similar chemical properties
Physical properties vary in a regular manner
Specifically melting point and boiling point

14. homologous series: trends in boiling points [366-368]
Gradual increase in boiling point, melting point, volatility with increasing carbons
Van der Waals forces
Higher molar mass = stronger forces
Increase slows down as the number of carbons increases, less percent increase in mass

15. homologous series: trends in boiling points [366-368]

16. 1, 2, and 3 carbons [ ]

17. 1, 2, and 3 alcohols, etc. Applies to other functional groups
Halogenalkanes, amines

18. IMF in organic compounds [380-381]
Alkanes, enes, ynes – van der Waals
Ester – dipole
Aldehyde – dipole
Ketone – dipole
Amine – hydrogen bonding
Alcohol – hydrogen bonding
Carboxylic acid – hydrogen bonding
Amide – hydrogen bonding

19. IMF in organic compounds [380-381]
Polarity ranking of functional groups
Amide>acid>alcohol>ketone~aldehyde> amine>ester>ether>alkane
Stronger IMF lead to higher boiling points and higher water solubility
As the carbon chain gets longer, water solubility decreases

20. IMF in organic compounds [380-381]
Exercises 5-8 page 382

21. Reactions of alkanes [382- 385]
Alkanes have strong bonds and are non polar, so low reactivity
The only reactions are:
Combustion (every hydrocarbon)
Substitution with chlorine and bromine

22. complete and incomplete combustion
Excess oxygen
CH + O2 → CO2 + H2O
Incomplete combustion
Insufficient oxygen
CH + O2 → CO + H2O

23. Balancing combustion reactions
Complete combustion of butane
Incomplete combustion of pentane
Complete combustion of ethanol
Exercise 9 page 385

24. Reactions of Alkanes [382- 385]
Alkanes can reaction with halogens in the presence of UV light to form hydrogen chloride and a substituted alkane
CH4 + Cl2 → CH3Cl + HCl
This happens via a mechanism involving a free radical

25. Reactions of Alkanes [382- 385]
A free radical is produced via homolytic fission
AB → A + B
each atoms remains with one lone electron
highly reactive free radical

26. Reactions of Alkanes [382- 385]
Initiation Cl2 + UV light → 2Cl Propagation Cl + CH4 → HCl + CH3 CH3 + Cl-Cl → CH3Cl + Cl Termination Cl + Cl → Cl2 or Cl + CH3 → CH3Cl or CH3 + CH3 → C2H6

27. Reactions of Alkenes [385-389]
Hydrocarbons with double or triple bonds are called unsaturated, all single bonds are called saturated because they are saturated with hydrogen
Alkenes can undergo addition and polymerization reactions

28. Addition reactions of alkenes [385-387]
Hydrogen, water, halogens, and hydrogen halides can be added across a double bond

29. Uses of addition reactions [385-387]
Bromination
If bromine is added to an alkene, the brown bromine turns colorless as it reacts
Hydration
Industrial production of ethanol
Hydrogenation
Industrial production of saturated fats

30. Polymerization of alkenes [387-389]
Important in manufacture of plastics
Polyethene polymer
Polychloroethene polymer (PVC)
Polypropene polymer

31. Reactions of Alkenes
Exercises page 389

32. Reaction of alcohols [390-392]
Oxidation
1 alcohol oxidized to aldehyde, then carboxylic acid
2 alcohol oxidized to ketone
3 alcohol cannot be oxidized

33. Reaction of alcohols [390-392]

34. distillation

35. reflux

36. Reaction of alcohols [390-392]

37. Exercises 13 and 14 page 392
Reaction of alcohols

38. Reactions of halogen alkanes [393-396]
Carbon connected to halogen is +
Susceptible to nucleophilic attack
Nucleophile reactant that attack at center of positive charge by donating electron pair
Good nucleophiles – OH-, NH3, CN-

39. Reactions of halogen alkanes [393-396]
1 halogen alkane undergo SN2 mechanism
2 halogen alkane undergo either SN1 or SN2
3 halogen alkane undergo SN1 mechanism
SN1 faster than SN2
Rate of hydrolysis 3 > 2 > 1

40. Reactions of halogen alkanes [393-396]
1 halogen alkane + dilute base

41. Reactions of halogen alkanes
Exercises 15 and 16 page 396

42. Reactions of halogen alkanes [393-396]
3 halogen alkane + dilute base

43. Reaction pathways
But-2-ene  butanone

44. 1-bromopentane  pentanoic acid
Reaction pathways
1-bromopentane  pentanoic acid