COMPOUNDS OF CARBON

1. COMPOUNDS OF CARBON Conceptual Chemistry Chapter 12

2. CARBON !!!! • Carbon atoms have the ability to link together and form molecules made up of many carbons atoms. • Add to this, the fact that any of the carbon atoms can also bond with atoms of other elements, and you see • the possibility of an endless number of different carbon-based molecules. • WHAT MAKES THE BONDING OF CARBON SO SPECIAL ???

3. Bonding of Carbon • 4 valence electrons • Charge • Strong covalent bonds

4. Life is based on carbon’s ability to bond with other carbon atoms to form diverse structures. The branch of chemistry that is the study of carbon-containing compounds has come to known as ORGANIC CHEMISTRY • Today, more than 13 million organic compounds are known, and about 100,000 new ones are added to that list each year. These include those discovered in nature and those synthesized in the laboratory. • In contrast, there are only 200,000 to 300,000 known INORGANIC compounds, those based on elements other than carbon.

5. EXAMPLES OF ORGANIC COMPOUNDS • Organic compounds that contain only carbon and hydrogen are called HYDROCARBONS • They differ from one another by the number of carbon and hydrogen atoms they contain. • The simplest hydrocarbon is METHANE, which is the main component of natural gas.

6. METHANE

7. Space-filling model 2-D rendition Stick structure

8. Space-filling model 2-D rendition Stick structure

9. Space-filling model 2-D rendition Stick structure

10. The hydrocarbon OCTANE has eight carbons per molecule and is a component of gasoline.

11. The hydrocarbon POLYETHYLENE contains hundreds of carbon and hydrogen atoms per molecule and is the plastic used to make many items, such as milk containers and plastic bags.

12. In all of the hydrocarbons that were discussed so far, each carbon atom is bonded to four neighboring atoms by four single covalent bonds. Such hydrocarbons are known as SATURATED HYDROCARBONS • The term saturated means that each carbon has as many atoms bonded to it as possible. • A hydrocarbon containing a multiple bond (either double or triple) is known as an UNSATURATED HYDROCARBON • Because of the multiple bonds, two of the carbons are bonded to fewer than four other atoms. These carbons are thus called unsaturated.

13. Saturated hydrocarbon A hydrocarbon in which each carbon atom is bonded to at least four other atoms.

14. Saturated

15. Unsaturated hydrocarbon A hydrocarbon in which a carbon atom is bonded to less than four other atoms. (This occurs when the hydrocarbon has a double or triple bond)

16. Saturated Unsaturated

17. Saturated Unsaturated

18. Saturated Unsaturated

19. Benzene

20. From “Chemicals of Life” chapter

21. http://www.saskschools.ca/curr_content/science10/unitc/fats.htmlhttp://www.saskschools.ca/curr_content/science10/unitc/fats.html http://recipes.howstuffworks.com/fat.htm

22. Carbon atoms can bond to one another and to hydrogen atoms in many ways, which results in an incredibly large number of hydrocarbons. • But carbon atoms can bond to atoms of other elements as well, further increasing the number of possible organic molecules. In organic chemistry, any atom other than carbon or hydrogen in an organic molecules is called a HETEROATOM • Organic molecules are classified according to the functional group they contain. A functional group is defined asa combination of atoms that behave as a unit

23. Organic Chemistry:Functional Groups

24. Origin of organic compounds • Naturally occurring organic compounds are found in plants, animals, and fossil fuels • All of these have a plant origin • All of these rely on the “fixing” of C from CO2 • Synthetic organic compounds are derived from fossil fuels or plant material

25. C C C C C Introduction • Most current research focuses on Organic • Originally from “organic” meaning life • Not just chemistry of life, chemistry of carbon • Exceptions: • oxides of carbon (CO2, CO) • carbonates,bicarbonates(NaHCO3,CaCO3) • cyanides (NaCN, etc) • One C with no H, or with metal • Carbon can form four bonds…

26. Carbon forms four bonds • Carbon can form four bonds, and forms strong covalent bonds with other elements • This can be represented in many ways …

27. Functional groups • Functional groups are parts of molecules that result in characteristic features • About 100 functional groups exist, we will focus on about 10 • Useful to group the infinite number of possible organic compounds • E.g. the simplest group is hydrocarbons • Made up of only C and H • Not really a functional “group” • Further divided into: • Alkanes, Alkenes, Alkynes, Aromatics

28. C C C C C C Hydrocarbons Alkanes Alkenes Alkynes Aromatics

30. Organic molecules can link to form POLYMERS !!! • Remember that polymers are long molecules that consist of repeating molecular units called MONOMERS. • If you recall, there are both naturally occurring and man-made polymers. Some carbon-based polymers occur naturally, while there are even some synthetic natural polymers.

31. The Structure and Properties of Polymers Also known as Bonding + Properties

32. What is a polymer? • A long molecule made up from lots of small molecules called • monomers.

33. All the same monomer • Monomers all same type (A) • A + A + A + A  • -A-A-A-A- • eg poly(ethene) polychloroethene PVC

34. Different monomers • Monomers of two different types A + B • A + B + A + B •  -A-B-A-B- • eg polyamides • polyesters

35. What decides the properties of a polymer? • Stronger attractive forces between chains = stronger, less flexible polymer. • Chains able to slide past each other = flexible polymer . • In poly(ethene) attractive forces are weak instantaneous dipole - induced dipole, will it be flexible or not? • Nylon has strong hydrogen bonds, why does this make it a strong fibre?

36. Thermoplastics (80%) • No cross links between chains. • Weak attractive forces between chains broken by warming. • Change shape - can be remoulded. • Weak forces reform in new shape when cold.

37. Thermosets • Extensive cross-linking formed by covalent bonds. • Bonds prevent chains moving relative to each other. • What will the properties of this type of plastic be like?

38. Longer chains make stronger polymers. • Critical length needed before strength increases. • Hydrocarbon polymers average of 100 repeating units necessary but only 40 for nylons. • Tensile strength measures the forces needed to snap a polymer. • More tangles + more touching!!!

39. Two examples of these are polysaccharides and polypeptides. • Polysaccharides arebiomolecular polymers made from hundreds to thousands of monosaccharide units. • The term saccharide is a synonym for CARBOHYDRATE • Carbohydrates are molecules of carbon, hydrogen, and oxygen produced by plants through photosynthesis. • Some examples of polysaccharides include starch, glycogen, and cellulose – all of which are based made up of glucose and are important components of the human diet.

41. Polypeptides are polymeric biomolecules that are made up of ten or more amino acids. • An amino acid consists of an amine group and a carboxylic acid group bonded to a central carbon atom. There are twenty amino acids that are the building blocks of proteins.

43. In addition to those naturally occurring polymers, there are even more synthetic, or man-made, polymers. What were some examples of the polymers that we have already discussed? • These synthetic polymers are more commonly referred to as “plastics” – but as much as these polymers are helpful to society – remember that there is a huge downfall. WE MUST RECYCLE !!!

44. With all of this talk about carbon and its unique bonding properties, it is important to note that the same carbon atoms are used repeatedly over and over on Earth. These atoms cycle between the Earth and the atmosphere.

45. THE CARBON CYCLE

46. What Is Carbon? • An element • The basis of life of earth • Found in rocks, oceans, atmosphere

47. Carbon Cycle • The same carbon atoms are used repeatedly on earth. They cycle between the earth and the atmosphere.

48. Plants Use Carbon Dioxide • Plants pull carbon dioxide from the atmosphere and use it to make food –— photosynthesis. • The carbon becomes part of the plant (stored food).

49. Animals Eat Plants • When organisms eat plants, they take in the carbon and some of it becomes part of their own bodies.

50. Plants and Animal Die • When plants and animals die, most of their bodies are decomposed and carbon atoms are returned to the atmosphere. • Some are not decomposed fully and end up in deposits underground (oil, coal, etc.).