Alkane, Alkene, Alkyne - WEEK 1.pptx

hydrocarbons

1. Lesson 11.1 Alkanes

2. describe the properties of alkanes; 1 At the end of the lesson, you should be able to: recognize the common examples and uses of alkanes; 2 write structural formulas for alkanes; and 3 name alkanes based on their structures. 4

3. These are a group of hydrocarbon compounds that contain carbon-carbon single (C-C) bonds and carbon-hydrogen (C-H) bonds only. It has a general formula of C n H 2n+2 where n is the number of carbon atoms (n=1, 2, 3, …). Their names end in - ane . Alkanes

4. Alkanes are insoluble in water, but are soluble in organic solvents such as toluene and chloroform. They are also less dense than water. TOLUENE - colorless, water-insoluble liquid with the smell associated with paint thinners. CHLOROFORM - colorless, toxic, sweet-tasting liquid formed by combining methane with chlorine. Properties of Alkanes

5. Alkanes may come into two forms: straight-chain and branched-chain. Straight-chain alkanes can be seen as a continuous row of carbons. Branched-chain alkanes are composed of a parent chain and alkyl groups. Naming Alkanes

6. In the case of nomenclature, straight-chain alkanes can be easily named with the first part of its name representing the number of carbon atoms and the suffix -ane representing the hydrocarbon group, alkane . For example, methane can be analyzed with meth- defining one carbon in the compound, and -ane signaling that the compound is purely an alkane. Naming Straight-Chain Alkanes

7. Number of Carbon Atoms Name (Molecular Formula) Kekule Structures Condensed Structure 1 methane (CH 4 ) CH 4 2 ethane (C 2 H 6 ) CH 3 CH 3 3 propane (C 3 H 8 ) CH 3 CH 2 CH 3 Table 1. Some examples of straight-chain alkanes and their corresponding nomenclature, Kekule structures, and condensed structures.

8. Number of Carbon Atoms Name (Molecular Formula) Kekule Structures Condensed Structure 4 butane (C 4 H 10 ) CH 3 CH 2 CH 2 CH 3 5 pentane (C 5 H 12 ) CH 3 CH 2 CH 2 CH 2 CH 3 6 hexane (C 7 H 14 ) CH 3 CH 2 CH 2 CH 2 CH 2 CH 3 Table 1. Some examples of straight-chain alkanes and their corresponding nomenclature, Kekule structures, and condensed structures.

9. To illustrate straight-chain alkanes, we can make use of the three main structural methods: Condensed Kekule , Skeletal structure . Drawing Straight-Chain Alkanes

10. How to draw the skeletal structure ( line angle formula ): They are represented by line segments connected through a zigzag direction. Endpoints represent carbon atoms. The symbols of carbon and hydrogen are not shown for the purpose of simplification. Drawing Straight-Chain Alkanes

11. Number of Carbon Atoms Name (Molecular Formula) Skeletal structures 3 propane (C 3 H 8 ) 4 butane (C 4 H 10 ) 5 pentane (C 5 H 12 ) 6 hexane (C 6 H 14 ) 7 heptane (C 7 H 16 ) Table 2. Some examples of straight-chain alkanes and their corresponding nomenclature and skeletal structures.

12. To name branched-chain alkanes, you may refer to the order of naming below: Naming Branched-Chain Alkanes Basic technique in naming branched-chain alkanes

13. In naming and drawing alkanes, the following terms should be considered: The parent chain is defined as the longest straight-chain alkane present in the hydrocarbon structure. Substituents are alkyl groups attached to one or more non-terminal carbon atoms belonging to parent chain. The locant represents the number of carbon where the substituents are attached. Naming Branched-Chain Alkanes

14. The order location-prefix-parent chain-suffix is followed. Prefixes are used to denote the number of identical substituents attached to the parent chain. In naming alkanes, two numbers are separated by a comma , while a word and a number are separated by a dash. Naming Branched-Chain Alkanes

15. Name the branched-chain alkane shown below. Naming Branched-Chain Alkanes

16. Step 1. Find the longest continuous chain in the molecule. This will serve as the parent chain. The longest chain is composed of nine carbons. Thus, it shall have the name, nonane .

17. Step 2. Identify the alkyl groups and their positions by looking at which carbon atom they are attached. Make sure that the position will yield the lowest number for the alkyl group . In the example given, the alkyl group attached in the parent chain is methyl.

18. To locate its position, you can count either from left to right, or right to left. If the counting starts at left, methyl will be connected to carbon-4; If the counting starts at right, methyl will be connected to carbon-6. Comparing the two, the first case gives the lowest number for methyl. Step 3. Using the order location-prefix-parent chain-suffix, we write the complete name of the molecule: 4-methylnonane .

19. Draw the skeletal structure of the branched-chain alkane: 2,4-diethylhexane. Step 1. Draw the parent chain first. Drawing Branched-Chain Alkanes In the example given, the parent chain is hexane.

20. Step 2. Number the carbons in the molecule and draw and place the alkyl groups based on the locations given by the name.

21. Alkanes are usually found in natural gas, petroleum deposits, and coal. Methane (CH 4 ), also known as natural gas, is a colorless , odorless , and gaseous alkane that is mostly used as fuel for heating homes, cooking, and electricity generation. Methane is commonly found together with other fossil fuels like coal and oil Uses of Alkanes

22. Name the branched-chain alkane shown below.

23. Step 1. Find the longest continuous chain in the molecule. This will serve as the parent chain. The longest chain is composed of eight carbons, thus shall have the name octane .

24. Step 2. Identify the alkyl groups and their positions by looking at which carbon atom they are attached. Make sure that the position will yield the lowest number for the alkyl group. The alkyl groups attached to the parent chain are both methyl groups.

25. To locate its position, you can count either from left to right, or right to left. If the counting starts at left, methyl groups will be connected to carbon-4; If the counting starts at right, methyl groups will be connected to carbon-5. Comparing the two, the first case gives the lowest number for the methyl groups. Step 3. Using the order location-prefix-parent chain-suffix, we write the name of the molecule: 4,4-dimethyloctane .

26. Alkanes are a group of hydrocarbons that contain carbon-carbon single (C-C) bonds and carbon-hydrogen (C-H) bonds only. 1 Alkanes have a general formula of C n H 2n+2 where n is the number of carbon atoms (n=1, 2, 3, …). Their names end in - ane . 2 In a condensed structure , only the symbols for carbon and hydrogen (and its subscripts) are shown while the line bonds are absent. 3

27. In a Kekule structure , the structure is drawn by explicitly writing the symbols of each atom and the bonds that exists between two atoms. 4 In a skeletal structure , the structure is represented by line segments connected through a zigzag direction. Endpoint represent carbon atoms. 5

28. Fill up the table below. Skeletal Structure of Alkane Name 2. 3. 4. 3,3,4,4-tetramethylheptane 5. 6-propyldecane

29. Lesson 11.2 Alkenes

30. describe the properties of alkenes; 1 At the end of the lesson, you should be able to: recognize the common examples and uses of alkenes; 2 write structural formulas for alkenes; and 3 name alkenes based on their structure. 4

31. These are a group of hydrocarbon compounds that contain carbon-carbon double (C=C) bonds . They are also known as olefins . It has a general formula of C n H 2n where n is the number of carbon atoms (n=2, 3, 4, …). Their names end in - ene . Alkenes

32. Alkenes are insoluble in water just like alkanes. They are also less dense than water. Alkenes are also highly flammable and very reactive. Properties of Alkenes

33. Simple alkenes can be easily named, with the first part of its name representing the number of carbon atoms , and the representing the hydrocarbon group, alkene . For example, ethene can be analyzed with eth- defining two carbons in the compound, and - ene signaling that the compound is an alkene. Naming Alkenes

34. Number of Carbon Atoms Name (Molecular Formula) Kekule Structure Condensed Structure 2 ethene (C 2 H 4 ) CH 2 =CH 2 3 propene (C 3 H 6 ) CH 3 CH=CH 2 4 1-butene (C 4 H 8 ) CH 2 =CHCH 2 CH 3 4 2-butene (C 4 H 8 ) CH 3 CH=CHCH 3 5 1-pentene (C 5 H 10 ) CH 2 =CHCH 2 CH 2 CH 3 5 2-pentene (C 5 H 10 ) CH 3 CH=CHCH 2 CH 3

35. It is also important to write down the position of the double bond in the alkene.. Consider the molecule below in naming an alkene. Naming Alkenes

36. Step 1. Find the longest continuous chain in the molecule. This will serve as the parent chain. Naming Alkenes The longest chain is composed of six carbons, thus shall have the name hexene.

37. Step 2. Identify the double bonds and their positions by looking at which carbon atom they are attached. Since two carbon atoms participate during double bond, the first carbon that you counted will provide the number for the alkene. Naming Alkenes

38. Step 3. Identify the alkyl groups and their positions by looking at which carbon atom they are attached. The direction we used in determining the location of the alkenes shall also be used in locating the alkyl groups. Naming Alkenes

39. Step 4. Combining the name of the alkyl group and the parent chain, we write now the complete name of the molecule: 3,4-dimethyl-1,4-hexadiene . Alternately, the molecule can also be named 3,4-dimethylhex-1,4-diene . Naming Alkenes

40. Consider the sample alkene, 2,4-dimethyl-1,3-hexadiene , in drawing the skeletal structure of alkenes when given only their names. Step 1. Draw the parent chain first. Drawing Alkenes The parent chain is 1,3-hexadiene.

41. Step 2. Number the carbons in the molecule and draw and place the alkyl groups based on the locations given by the name. Drawing Alkenes

42. Draw the skeletal formula of the straight-chain alkene, 2,4,6-octatriene.

43. Draw the skeletal formula of the straight-chain alkene, 2,4,6-octatriene. Step 1. Identify the prefix and the number of carbon atoms present in the straight-chain alkene. The prefix used is oct- , which corresponds to eight carbon atoms. Step 2. Identify the position of the double bond. The locants indicate that there are three double bonds which are positioned at the second, fourth, and sixth carbon atoms.

44. Draw the skeletal formula of the straight-chain alkene, 2,4,6-octatriene. Step 3. Draw the skeletal formula of the straight-chain alkene. The parent chain contains eight carbon atoms, as shown below, where the double bonds are positioned in the second, fourth, and sixth carbon atoms.

45. Alkenes, under constitutional isomers, form positional isomers , or molecules with very similar structure except for the location of their functional groups. Below is an example of positional isomers of octene. Positional Isomers Positional isomers of octene

46. Alkenes serve an important role in most biological molecules. Linoleic acid (C 18 H 32 O 2 ), also known as omega-6 fatty acid, is an alkene that naturally exist in plants. It serves as an important biomolecule for their nutrition as they use it as a starting material in the production of prostaglandins. Examples of Alkenes and Its Uses linoleic acid

47. β-carotene (C 40 H 56 ). It serves as a precursor to the synthesis of vitamin A. When vitamin A undergoes an enzymatic reaction, a series of reaction follows in the retina, which then enables our eyes to sense vision in bright, dim, and colored light. Examples of Alkenes and Its Uses β-carotene

48. Alkenes are a group of hydrocarbons that contain carbon-carbon double (C=C) bonds. They are also known as olefins . 1 Alkenes have a general formula of C n H 2n where n is the number of carbon atoms (n=2, 3, 4, …). Their names end in -ene . 2 Alkenes are generally insoluble in water just like alkanes. They are also less dense than water. 3

49. Fill up the table below . Skeletal Structure of Alkene Name 1. 2. 3. 4. 1,4,6-octatriene 5. 3-ethyl-3-heptene

50. Lesson 11.3 Alkynes

51. describe the properties of alkynes; 1 At the end of the lesson, you should be able to: recognize the common examples and uses of alkynes; 2 write structural formulas for alkynes; and 3 name alkynes based on their structure. 4

52. These are a group of hydrocarbon compounds that contain carbon-carbon triple (C≡C) bonds . It has a general formula of C n H 2n-2 where n is the number of carbon atoms (n=2, 3, 4, …) Their names end in - yne . Alkynes

53. Alkenes are insoluble in water and are slightly soluble in some organic solvents. Most are less dense than water and some are explosives. Some are used in pharmacy, manufacturing of plastic, and artificial ripening of fruits. Properties of Alkynes

54. Simple alkynes can be easily named, with the first part of its name representing the number of carbon atoms , and the suffix - yne representing the hydrocarbon group, alkyne . For example, ethyne can be analyzed with eth- defining two carbons in the compound, and - yne signaling that the compound is an alkyne. Naming Alkynes

55. Number of Carbon Atoms Name (Molecular Formula) Kekule Structure Condensed Structure 2 ethyne (C 2 H 2 ) CH≡CH 3 propyne (C 3 H 4 ) CH≡CCH 3 4 1-butyne (C 4 H 6 ) CH≡CCH 2 CH 3 4 2-butyne (C 4 H 6 ) CH 3 C≡CCH 3

56. It is also important to write down the position of the triple bond in the alkyne. Consider the molecule below in naming an alkene. Naming Alkynes

57. Step 1. Find the longest continuous chain in the molecule. This will serve as the parent chain. Naming Alkynes The longest chain is composed of seven carbons, thus shall have the name heptyne.

58. Step 2. Identify the triple bonds and their position/s by looking at which carbon atom they are formed. Since two carbon atoms participate during triple bond, the first carbon that you counted will provide the number for the alkyne. Naming Alkynes

59. Step 3. Identify the alkyl groups and their positions by looking at which carbon atom they are attached. The direction we used in determining the location of the alkynes shall also be used in locating the alkyl groups. Step 4. Combining the name of the alkyl group and the parent chain, we write now the name of the molecule: 2,6-dimethyl-3-heptyne . Alternately, the molecule can also be named 2,6-dimethylhept-3-yne . Naming Alkynes

60. Consider the sample alkyne, 4,4-diethyl-2-hexyne , in drawing the skeletal structure of alkynes when given only their names. Step 1. Draw the parent chain first. Drawing Alkynes The parent chain is 2-hexyne.

61. Step 2. Number the carbons in the molecule and draw and place the alkyl groups based on the locations given by the name. Drawing Alkynes

62. Draw the skeletal formula of the straight-chain alkyne, 1,3-heptadiyne.

63. Draw the skeletal formula of the straight-chain alkyne, 1,3-heptadiyne. Step 1. Identify the prefix and the number of carbon atoms present in the straight-chain alkyne. The prefix used is hept- , which corresponds to seven carbon atoms. Step 2. Identify the positions of the triple bonds. The locants indicate that there are two triple bonds which are positioned at the first and third carbon atoms.

64. Draw the skeletal formula of the straight-chain alkyne, 1,3-heptadiyne. Step 3. Draw the skeletal formula of the straight-chain alkyne. The parent chain contains seven carbon atoms, as shown below, where the triple bonds are positioned in the first and third carbon atoms.

65. Alkynes are very rare hydrocarbons, and yet they still useful to metal works and pharmacy. Ethyne (C 2 H 2 ), also known as acetylene, is an alkyne. It exists as a colorless and flammable gas. During the 20 th century, it is widely used in torches for metal works, as well as in portable lamps and lanterns (water and calcium carbide were used to produce acetylene in these devices) where it produces bright flame. Examples of Alkynes and Its Uses

66. Another example of an alkyne is methylpentynol (C 6 H 10 O). This sedative is used as an over-the-counter drug for people who experiences insomnia. One unique compound which contains alkyne is ichthyothereol (C 14 H 14 O 2 ). This compound is naturally secreted by poison dart frogs. Examples of Alkynes and Its Uses

67. Alkynes are a group of hydrocarbons that contain carbon-carbon triple (C≡C) bonds. 1 Alkenes have a general formula of C n H 2n-2 where n is the number of carbon atoms (n=2, 3, 4, …). Their names end in -yne . 2

68. Fill up the table below. Skeletal Structure of Alkyne Name 2. 3. 4. 2-hexyne 5. 4-methyl-1-pentyne