1. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Principles of Organic Chemistry Unit 3 SCH 4C

2. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Organic Chemistry Organic chemistry: Organic chemistry: the study of the compounds that contain carbon as the building blocks. Organic compounds are made up of carbon and only a few other elements. chief among these are hydrogen, oxygen, and nitrogen also present are sulfur, phosphorus, and halogens

3. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Importance of Organic Chemistry Organic chemicals affect virtually every facet of our lives: Organic chemicals affect virtually every facet of our lives: Products such as clothes, foods, medicines, gasoline, refrigerants, and soaps are composed almost solely of organic compounds Carbohydrates, lipids, proteins, enzymes, nucleic acids, hormones, vitamins, and almost all other chemicals in living systems are organic compounds.

4. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Learning Check: Which of the following represents an organic compound? Why? a)CH 3 OHb) C 6 H 12 O 6 c)NaOHd) NaHCO 3 e) C 5 H 12 f) HCN

5. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Organic Structure Molecular formula:Molecular formula: indicates the type and number of atoms present in a molecule; ie) C 2 H 2 Structural formula:Structural formula: shows the atoms present in a molecule as well as how the bonds connect them

6. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Learning Check: Provide the molecular formula for each of the following organic compounds.

7. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Characteristics of Organic Compounds 1. All organic compounds contain carbon atoms and most contain hydrogen atoms. Carbon always forms four covalent bonds. Hydrogen always forms one covalent bond.

8. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Characteristics of Organic Compounds 2. Carbon forms single, double, and triple bonds to other carbon atoms.

9. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Characteristics of Organic Compounds Carbon forms single and double bonds to oxygen atoms.

10. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Learning Check: Fill in all the H’s and lone pairs in each compound. a) C−C=C−C b) C−C−O−C−C c) O=C−C−C

11. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Learning Check: Provide two possible structures for each of the following molecules. a)C 2 H 6 O b) C 5 H 10 c) C 3 H 7 N Start by drawing the carbon chain!

12. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Drawing Organic Molecules: Condensed Structures  In a condensed structure, all of the atoms are drawn in, but the two-electron bond lines and lone pairs on oxygen are generally omitted. A carbon bonded to 3 H’s becomes CH 3 A carbon bonded to 2 H’s becomes CH 2

13. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Drawing Organic Molecules: Condensed Structures A carbon bonded to 1 H becomes CH Some bond lines can be drawn in for effect or to show specific bonding.

14. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Learning Check: Provide a condensed structure for each of the following molecules.

15. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Drawing Organic Molecules: Skeletal or Line Structures When drawing a skeletal or line structure: assume there is a carbon atom at the junction of any two lines or at the end of any line (every end and every bend) assume there are enough hydrogens around each carbon to give it four bonds draw in all atoms other than carbon and the hydrogens directly bonded to them

16. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Learning Check: Provide a skeletal structure for each of the following molecules.

17. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Learning Check: Provide a structural formula for the following skeletal structures.

18. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Hydrocarbons

19. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Hydrocarbons Hydrocarbon: Hydrocarbon: a compound composed of only carbon and hydrogen.

20. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Alkanes Alkanes: Alkanes: hydrocarbons containing only carbon-carbon single bonds. All alkanes are considered saturated hydrocarbons because they have the maximum number of H atoms per C atom. Alkanes that contain chains of C atoms but no rings are acyclic alkanes and have the general formula C n H 2n+2 The first two alkanes are methane and ethane.

21. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Alkanes line-angle formula: line-angle formula: A line represents a carbon-carbon bond and a vertex and a line terminus represent a carbon atom. Hydrogen atoms are not shown in line-angle formulas.

22. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Constitutional Isomerism Constitutional isomers: Constitutional isomers: compounds that have the same molecular formula but different structural formulas (different connectivity). For the molecular formulas CH 4, C 2 H 6, and C 3 H 8, only one structural formula is possible; there are no constitutional isomers for these molecular formulas. For the molecular formula C 4 H 10, two constitutional isomers are possible. We can attach the atoms together in two different ways.

23. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Conformation The following two representations of propane are equivalent: The bends in a carbon chain don’t matter when it comes to identifying different compounds. conformationMolecules which have the same molecular formula, are connected the same way but are drawn differently, differ in conformation.

24. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Constitutional Isomerism Problem:Problem: do the structural formulas in each set represent the same compound or constitutional isomers?

25. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Constitutional Isomerism Problem:Problem: draw structural formulas for the five constitutional isomers of molecular formula C 6 H 14

26. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Alkenes and Alkynes Alkene: Alkene: a hydrocarbon that contains one or more carbon-carbon double bonds. ethylene is the simplest alkene. Alkyne: Alkyne: a hydrocarbon that contains one or more carbon-carbon triple bonds. acetylene is the simplest alkyne.

27. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Alkenes and Alkynes Alkenesalkynes Alkenes and alkynes are two families of organic multiple bonds molecules that contain multiple bonds. Alkenes have the general formula C n H 2n Alkynes have the general formula C n H 2n–2

28. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Alkenes and Alkynes: Condensed Structural Formula When drawing the condensed structures of alkenes and alkynes we keep the multiple-bond

29. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Naming Acyclic Hydrocarbons: The name of a hydrocarbon has three parts: Indicates the name of the branch and its location on the main carbon chain Indicates the number of carbon atoms in the main chai n Indicates the functional group or type of hydrocarbon ane – alkane ene – alkene yne - alkyne PrefixRootSuffix ++

30. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division IUPAC Names The IUPAC name of an alkane with an unbranched chain of carbon atoms consists of two parts: (1) a root: the number of carbon atoms in the chain. -ane(2) the suffix -ane: shows that the compound is a saturated hydrocarbon.

31. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division IUPAC Names ( Unbranched Alkanes)

32. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division The name of an alkane with a branched chain of carbon atom consists of: The root and suffix: the longest chain of carbon atoms and the ending –ane. substituent names: the groups bonded to the parent chain IUPAC Names ( Branched Alkanes)

33. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division IUPAC Names Alkyl group: Alkyl group: a substituent group derived from an alkane by removal of a hydrogen atom. ane ylnamed by dropping the -ane from the name of the parent alkane and adding the suffix -yl.

34. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division IUPAC Naming Rules ane. 1. The name for an alkane with an unbranched chain of carbon atoms consists of a root showing the number of carbon atoms and the ending -ane. 2. For branched-chain alkanes, the longest chain of carbon atoms is the parent chain and its name is the root name. 3. Name and number each substituent on the parent chain; use a hyphen to connect the number to the name.

35. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division IUPAC Naming Rules (con’t) 4. If there is one substituent, number the parent chain from the end that gives the substituent the lower number.

36. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division IUPAC Naming Rules (con’t) 5. If the same substituent occurs more than once: Number the parent chain from the end that gives the lower number to the substituent encountered first. Indicate the number of times the substituent occurs by a prefix di-, tri-, tetra-, penta-, hexa-, and so on. Use a comma to separate position numbers.

37. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division IUPAC Naming Rules (con’t) 6. If there are two or more different substituents: list them in alphabetical order. number the chain from the end that gives the lower number to the substituent encountered first. If there are different substituents in equivalent positions on opposite ends of the parent chain, give the substituent of lower alphabetical order the lower number.

38. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Learning Check: Give the IUPAC name for the following compounds.

39. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Nomenclature of Alkenes and Alkynes HOW TO Name an Alkene or Alkyne Give the IUPAC name of the following alkene and alkyne. Step [1] Find the longest chain that contains the double or triple bond.

40. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Nomenclature of Alkenes and Alkynes HOW TO Name an Alkene or Alkyne Step [1] Find the longest chain that contains the double or triple bond. Compounds containing a carbon-carbon double bond end with “ene” Compounds containing a carbon-carbon triple bond end with “yne” Step [2] Number the carbon chain from the end that gives the multiple bond the lower number. Step [3] Number and name the substituents Arrange side groups alphabetically and write the name.

41. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Alkenes - IUPAC Names Examples

42. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Alkynes - IUPAC Names ynefollow the same rules as for alkenes, but use the ending -yne to show the presence of the triple bond.

43. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Nomenclature: Provide a IUPAC name for each of the following.

44. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Sample Questions Provide a IUPAC name for each of the following.

45. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Physical Properties The most important physical property of alkanes and cycloalkanes is their almost complete lack of polarity.

46. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Melting and boiling points Alkanes are nonpolar compounds and the only interaction between their molecules are the very weak London dispersion forces. Boiling points of alkanes are lower than those of almost any other type of compound of the same molecular weight. In general, the boiling points and melting points of alkanes increase with increasing lengths carbon chains. Smaller alkanes are gases at room temperature, whereas larger alkanes are liquids. Physical Properties

47. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Physical Properties of Some Unbranched Alkanes

48. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Physical Properties Alkanes that are constitutional isomers are different compounds and have different physical and chemical properties.

49. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Physical Properties Solubility: a case of “like dissolves like”. Alkanes are not soluble in water; they are unable to form hydrogen bonds with water. Alkanes are soluble in each other. Alkanes are also soluble in other nonpolar organic compounds, such as toluene and diethyl ether. Density The average density of the liquid alkanes listed in Table 11.4 is about 0.7 g/mL; that of higher-molecular-weight alkanes is about 0.8 g/mL. All liquid and solid alkanes are less dense than water (1.0 g/mL) and, because they are insoluble in water, they float on water.

50. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Focus on the Environment Fossil Fuels Natural gas is used as a fuel source for cooking and heating Petroleum is a complex mixture that must be separated it into usable fractions

51. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Physical Properties of Unsaturated Hydrocarbons Alkenes and alkynes are nonpolar compounds. The only attractive forces between their molecules are London dispersion forces. Their physical properties are similar to those of alkanes with the same carbon skeletons. Alkenes and alkynes are insoluble in water but soluble in one another and in nonpolar organic liquids. Alkenes and alkynes that are liquid or solid at room temperature have densities less than 1.0 g/mL; they float on water.

52. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Reactions of Alkanes Oxidation (combustion) Oxidation of hydrocarbons, including alkanes is the basis for their use as energy sources for heat [natural gas, liquefied petroleum gas (LPG), and fuel oil] and power (gasoline, diesel fuel, and aviation fuel).

53. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Question: Provide a balanced chemical equation for the complete combustion of: a) 2-methylbutane b)

54. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Reactions Reaction with halogens (halogenation) Halogenation of an alkane is a substitution reaction.

55. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Question: Show the two possible organic products from the chlorination of butane:

56. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Reactions of Alkenes The most common reaction is addition

57. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Addition of a Halide Addition of HX (HCl, HBr, or HI) to an alkene gives a haloalkane. H adds to one carbon of the C=C and X to the other. regioselective.reaction is regioselective. Markovnikov’s rule:Markovnikov’s rule: H adds to the less substituted carbon and X to the more substituted carbon.

58. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Sample Questions Draw the structural formula of the product and name the alkene and alkane in each of the following addition reactions:

59. © 2007 Thomson Learning, Inc. All rights reserved HFCC Science Division Addition of H 2 O hydration Addition of water is called hydration hydration is acid catalyzed, most commonly by H 2 SO 4 H adds to the less substituted carbon and OH adds to the more substituted carbon.