Carbon has four valence electrons. A carbon atom can form four single covalent bonds,

1. Carbon compounds form the structures of a whale’s cells and control reactions that take place in those cells. The instructions for these processes are stored in organic compounds.

2. An organic compound contains carbon and hydrogen, often combined with a few other elements such as oxygen and nitrogen. There are millions of organic compounds—more than 90 percent of all known compounds.

3. Carbon has four valence electrons. A carbon atom can form • four single covalent bonds, • a double bond and two single bonds, or • a triple bond and a single bond. Most of the bonds in organic compounds are carbon-to-carbon bonds or carbon-to-hydrogen bonds.

4. Forms of Carbon What are three forms of carbon? Diamond, graphite, and fullerenes are forms of carbon.

5. Forms of Carbon Diamond Diamond is an example of a network solid, in whichall the atoms are linked by covalent bonds. • Covalent bonds connect each carbon atom to four other carbon atoms. • The three-dimensional structure is rigid, compact, and strong. • Diamond is harder than other substances because cutting a diamond requires breaking many covalent bonds.

6. Forms of Carbon Graphite Graphite is extremely soft and slippery. • Carbon atoms are arranged in widely spaced layers. • Within each layer, carbon atoms form strong covalent bonds with three other carbon atoms. • Between layers the bonds are weak, so layers slide easily past one another.

7. Forms of Carbon Fullerenes Fullerenes are large hollow spheres or cages of carbon. On the surface of a 60-carbon fullerene (C60), the atoms form alternating hexagons and pentagons. The C60 molecule is called buckminsterfullerene.

8. Forms of Carbon A In diamond, carbon atoms are arranged in a rigid, three-dimensional network. B In graphite, the atoms are arranged in layers. C In fullerenes, carbon atoms are arranged in hollow spheres. Diamond Graphite Buckminsterfullerene

9. Saturated Hydrocarbons What factors determine the properties of a hydrocarbon? A hydrocarbon is an organic compound that contains only the elements hydrogen and carbon. Factors that determine the properties of a hydrocarbon are the number of carbon atoms and how the atoms are arranged.

10. Saturated Hydrocarbons In a saturated hydrocarbon, all of the bonds are single bonds. • A saturated hydrocarbon contains the maximum possible number of hydrogen atoms for each carbon atom. • Saturated hydrocarbons are also called alkanes. Their names end in –ane.

11. Saturated Hydrocarbons A hydrocarbon molecule can contain one carbon atom, as in methane, or more than 30 carbon atoms, as in asphalt. The carbon atoms can be arranged in a straight chain, a branched chain, or a ring.

12. Saturated Hydrocarbons Microorganisms in the stomachs of a cow produce more than 500 liters of methane (CH4) per day.

13. Saturated Hydrocarbons Straight Chains • A molecular formula shows the type and number of atoms in a molecule of the compound. • A structural formula shows how those atoms are arranged. • The boiling point of a straight-chain alkane depends on the number of carbon atoms. Methane and propane are gases at room temperature. Pentane and octane are liquids.

14. Saturated Hydrocarbons

15. Saturated Hydrocarbons

16. Saturated Hydrocarbons

17. Saturated Hydrocarbons

18. Saturated Hydrocarbons Branched Chains Butane and isobutane both have a molecular formula of C4H10, but their structural formulas are different.

19. Saturated Hydrocarbons Compounds with the same molecular formula but different structural formulas are isomers. • In isobutane, there is a branch at the point where a carbon atom bonds to three other carbon atoms. • Differences in structure affect some properties of isomers. Butane boils at –0.5°C, but isobutane boils at –11.7°C.

20. Saturated Hydrocarbons Rings Carbon atoms in cyclobutane are linked in a four-carbon ring.

21. Saturated Hydrocarbons In a cycloalkane, each carbon atom forms bonds with two other carbon atoms and two hydrogen atoms. • So cyclobutane (C4H8) molecules have two fewer hydrogen atoms than butane (C4H10) molecules. • Most ring alkanes, or cyclic hydrocarbons, have rings with five or six carbons.

22. Unsaturated Hydrocarbons What are the three types of unsaturated hydrocarbons? A hydrocarbon that contains one or more double or triple bonds is an unsaturated hydrocarbon. There are three types of unsaturated hydrocarbons—alkenes, alkynes, and aromatic hydrocarbons.

23. Unsaturated Hydrocarbons Alkenes There is a double bond between the two carbon atoms in ethene. Hydrocarbons that have one or more carbon-carbon double bonds are alkenes. The names of alkenes end in –ene.

24. Unsaturated Hydrocarbons Many fruit-bearing plants produce ethene (C2H4), which controls the rate at which fruits, such as this tomato, ripen.

25. Unsaturated Hydrocarbons Alkynes Ethyne (C2H2) is an alkyne. Alkynes are straight- or branched-chain hydrocarbons that have one or more triple bonds. Alkyne names end in –yne.

26. Unsaturated Hydrocarbons Alkynes are the most reactive hydrocarbon compounds. Ethyne (C2H2), also known as acetylene, is used in torches that cut metal or weld them together.

27. Unsaturated Hydrocarbons Aromatic Hydrocarbons Benzene (C6H6) is an unsaturated hydrocarbon with a ring structure.

28. Unsaturated Hydrocarbons Although the formula for Benzene shows alternating single and double bonds, the six bonds in the ring are identical. All six carbon atoms share six of the valence electrons. Hydrocarbons that contain similar ring structures are known as aromatic hydrocarbons. The name was chosen because many of these compounds have strong aromas, or odors.

29. Fossil Fuels What are the three main fossil fuels? Three types of fossil fuels are coal, natural gas, and petroleum. Fossil fuels are mixtures of hydrocarbons that formed from the remains of plants or animals.

30. Fossil Fuels Coal • Giant tree ferns and other plants were buried in swamps. • After millions of years of pressure, the plant remains produced a mixture of hydrocarbons. • Most of the hydrocarbons in coal are aromatic hydrocarbons with high molar masses. • Coal produces more soot than other fossil fuels.

31. Fossil Fuels The ferns shown are similar to ferns that lived millions of years ago. Imprints of ferns in coal are evidence that coal formed when plant remains were compressed.

32. Fossil Fuels Natural Gas • Natural gas formed from the remains of marine organisms. • The main component of natural gas is methane. Natural gas also contains ethane, propane, and isomers of butane. • Natural gas is used for heating and cooking. • Deposits of natural gas are found along with coal and petroleum.

33. Fossil Fuels Petroleum • Petroleum also formed from marine organisms. • Petroleum is pumped from deep beneath Earth’s surface. • Petroleum is a complex liquid mixture of hydrocarbons, mainly long-branched alkanes and alkenes.

34. Fossil Fuels Petroleum is separated into mixtures called fractions. Distillation Tower Heating Burner

35. Fossil Fuels Petroleum is separated into mixtures called fractions. Distillation Tower Heating Burner

36. Fossil Fuels Petroleum is separated into mixtures called fractions. Distillation Tower Crude oil Heating Burner

37. Fossil Fuels Petroleum is separated into mixtures called fractions. Distillation Tower Crude oil vapors Crude oil Heating Burner

38. Fossil Fuels Petroleum is separated into mixtures called fractions. Distillation Tower Crude oil vapors Crude oil Heating Burner

39. Fossil Fuels Petroleum is separated into mixtures called fractions. Distillation Tower Crude oil vapors Crude oil Heating Burner

40. Fossil Fuels Petroleum is separated into mixtures called fractions. Distillation Tower Crude oil vapors Crude oil Heating Burner

41. Fossil Fuels Petroleum is separated into mixtures called fractions. Distillation Tower Crude oil vapors Crude oil Heating Burner

42. Fossil Fuels Petroleum is separated into mixtures called fractions. Distillation Tower Crude oil vapors Crude oil Heating Burner

43. Combustion of Fossil Fuels What are the two primary products of the combustion of fossil fuels? The primary products of the complete combustion of fossil fuels are carbon dioxide and water.C3H8 + 5O2  3CO2 +4H2O (complete combustion)

44. Combustion of Fossil Fuels Incomplete Combustion If there is not enough oxygen available for complete combustion of all the fuel, carbon monoxide is produced. Carbon monoxide is a colorless, odorless gas that is poisonous. It keeps hemoglobin from carrying oxygen to cells. 2C3H8 + 7O2 6CO + 8H2O (incomplete combustion)

45. Combustion of Fossil Fuels Acid Rain Sulfur dioxide and nitrogen oxides released into the atmosphere by the combustion of fossil fuels forms sulfuric acid and nitric acid. These acids damage stone structures, metal, and concrete.

46. Assessment Questions • Graphite is soft and slippery because its carbon atoms • are arranged in layers with weak attractions between layers. • have a large, interlocking network. • contain individual atoms with very weak bonds to other carbon atoms. • share a weak bond with hydrogen atoms.

47. Assessment Questions • Graphite is soft and slippery because its carbon atoms • are arranged in layers with weak attractions between layers. • have a large, interlocking network. • contain individual atoms with very weak bonds to other carbon atoms. • share a weak bond with hydrogen atoms.ANS: A

48. Assessment Questions • In general, the boiling point of a hydrocarbon increases as • the number of hydrogen bonds between molecules increases. • the number of carbon atoms in the chain increases. • the branching of the carbon chain increases. • the number of oxygen atoms in the molecule increases.

49. Assessment Questions • In general, the boiling point of a hydrocarbon increases as • the number of hydrogen bonds between molecules increases. • the number of carbon atoms in the chain increases. • the branching of the carbon chain increases. • the number of oxygen atoms in the molecule increases.ANS: B

50. Assessment Questions • An unsaturated hydrocarbon always contains • double bonds between carbon atoms. • double or triple bonds. • at least one ring in its structure. • at least one atom that is neither carbon nor hydrogen.