Organic Chemistry

1. Organic Chemistry Unit 14 Text Chapters 22-23

2. What is Organic Chemistry? • The study of carbon and most carbon compounds • “The chemistry of life” • … but includes far more compounds than those made by living things.

3. Properties of Organic compounds • Remember they a generally covalent and highly symmetrical • Generally low melting points • Low boiling points • Soft (if not a gas) • nonconducting

4. Bonding of Carbon Atoms • Carbon can form so many compounds because carbon atoms easily form 4 covalent bonds • Can be single, double, or triple covalent bonds

5. Bonding of Carbon Atoms • Lewis Dot Diagram of Carbon in ground state • Lewis dot diagram of bonded carbon atom • Enables four covalent bonds • Tetrahedral shape • Angles are actually 109.50

6. Some Terminology • Organic compounds containing only single bonds (between carbon atoms) are said to be saturated. • Organic compounds containing one or more double or triple bonds are called unsaturated compounds.

7. More Terminology • Hydrocarbons - organic compounds that contain only hydrogen and carbon atoms • Homologous series - group of related compounds in which each member differs from the one before by one additional unit. • Alkanes • Alkenes • Alkynes

8. Alkanes • Only contain single bonds between carbon atoms • Therefore, are all saturated. • As the number of carbon atoms in this homologous series increases, so does the boiling point (Van der Waals review) example: CH4 is lower than C2H6 • Their names end with “-ane”

9. Common Alkanes • Methane - Natural gas • Ethane - Also natural gas • Propane - outdoor grills/home heating • Butane - lighters • Pentane, Hexane, Heptane, Octane, Nonane, Decane - all found in gasoline • Candle wax - 20 or more carbon atoms • Road Tar - 40 or more carbon atoms

10. General Formula For Alkanes • Each successive carbon adds two more hydrogen atoms • CnH2n+2

11. Alkenes • Each member of alkene series contains one double covalent bond • Names are same as for alkanes, except change ending to “-ene”. • Unsaturated • CnH2n • Di-enes have 2 double bonds tri-enes have three

12. Alkynes • Contain one triple bond between carbon atoms • Names are same as for alkanes, except change ending to “-yne”. • Ethyne (common name “acetylene” - used in welding torches) • Alkynes can also be diyne and tryine

13. Alkynes • CnH2n-2 • Pull out Reference Tables… • Table P - Organic Prefixes • Table Q - homologous series & general formulas

14. Chemistry Humor • According to a chemist, why is the world so diverse? • Because it's made up of alkynes of people.

15. Let’s Keep some terms straight… • Molecular formula - represents the actual atoms in a molecule • Reminder - empirical formula is the simplest integer ratio in which atoms combine in a compound. • Structural Formula - attempts to show the kinds and numbers of atoms, but also the bonding patterns and approximate shapes • Condensed structural formulas

16. Isomers • Starting with butane there’s more than one way to combine the carbon and hydrogen atoms. • When a molecular formula can be represented by more than one structural arrangement, the compounds are called isomers of one another.

17. Isomers • Even though they have the same molecular formula, isomers have different chemical and physical properties. • Different boiling points • Different reactivities • As the number of carbon atoms increases, so does the number of possible isomers.

18. Naming Organic Compounds • Compounds with branched chains must be given different names because they have different chemical and physical properties. • Naming rules are governed by IUPAC (International Union of Pure and Applied Chemistry)

19. Naming Organic Compounds • Step 1 - Find the longest continuous chain of carbon atoms • The compound will be named based on its longest chain. • For example, if the longest chain is 6, then the compound will be named as a hexane.

20. Naming Organic Compounds • Step 2 - Identify attached Alkyl Groups • Side chain of carbon(s). Use prefixes from table P • Step 3 - Assign numbers to the carbon atoms in the longest chain. • must number from the end that will give the lowest number for the attached group.

21. Naming Organic Compounds • Step 4 - Name the compound by stating the location of the attached chain, the alkyl group, then the main branch name

22. Naming Organic Compounds • Some additional naming info… • If there is more than one of the same type of group attached to the parent chain, then a prefix is used • di- means two; tri- means three; tetra- means four • #’s are used to indicate the specific carbon(s) on the main chain to which each group is attached

23. Functional Groups • Functional Groups - are atoms or groups of atoms that replace hydrogen in a hydrocarbon, and give the compound distinctive chemical and physical properties.

24. Organic Halides (“Halocarbons”) • When a halogen (F, Cl, Br, or I) replaces a hydrogen on an alkane, the compound is called an organic halide (or halocarbon). • The functional group is the attached halogen. • Named by citing the location of the halogen attached to the chain. (refrigerants like freon)

25. Alcohols • Alcohols - organic compounds where one hydrogen of a hydrocarbon is replaced by an -OH group (called a hydroxyl group) • The -OH group resembles the hydroxide ion, but it isn’t the same. It doesn’t form hydroxide ion in water. Alcohols are not bases! Don’t be fooled! • Therefore, alcohols are nonelectrolytes

26. Alcohols • The hydroxyl group is polar, though, which allows alcohols to dissolve in water. • Name by changing corresponding alkane ending “-e” to “-ol”

27. Ketones • Ketones formed when carbonyl group is attached to an interior carbon atom that is attached to two other carbon atoms. • Named by replacing final “-e” of corresponding alkane name with “-one” • Propanone’s common name is “acetone” - nail polish remover. • Ketones are often used as solvents (because both polar and nonpolar

28. Aldehydes • Aldehydes are organic compounds in which the carbonyl group is on the end carbon • Named by substituting “-al” for the final “-e” of the corresponding alkane name. • Methanal’s common name is “formaldehyde”

29. Organic Acids • Organic Acids are a homologous series • Functional group is carboxyl group (-COOH) • Name comes from corresponding hydrocarbon, but replace ending “-e” with “-oic acid” • Ethanoic acid (common name “acetic acid”, which is found in vinegar)

30. Organic Acids • Most organic compounds are nonelectrolytes, but organic acids are weak electrolytes. • Reference Table R

31. Ethers • Series of organic compounds in which two carbon chains are joined together by an oxygen atom bonded between two carbon atoms. • Named using alkyl group names followed by “ether”.

32. Esters • Esters are organic compounds whose type formula is R-CO-ORI • Part comes from an organic acid, and the RI part comes from an alcohol • Esters have strong, fragrant odors.

33. Amines • Amines are formed when one of the hydrogens of ammonia is replaced by an alkyl group. • Named by taking the alkane name and change the ending “-e” to “-amine”, and number the alkane chain to show the location of the amine group.

34. Amino Acids • Amino acids contain the carboxylic group (-COOH) and an amine. • The amine group is attached to the carbon adjacent to the acid group. • Amino acids are the building blocks of protein. • The body must take in (ingest) 10 essential amino acids, because the body can’t produce them. The remaining amino acids can be synthesized.

35. Amides • Amides are compounds formed by combination of two amino acids. • Additional amino acids can be linked, forming “polypeptides”, and eventually, proteins.

36. isomers two or more compounds that contain the same number of atoms of the same elements but differ in structural arrangement and properties • The first 3 alkanes have no isomers • (they can only be drawn (and named) 1 way). • Lets draw and name all the Isomers of Butane C4H10

37. Esterification • Esterification - The organic reaction between an organic acid and an alcohol to produce an ester plus water. • Esters are named by using the alkyl name of the alcohol followed by the acid group modified to end in “-oate”.

38. Saponification • The name of the organic reaction that makes soap. • An ester reacts with an inorganic base to produce an alcohol and soap. Soap

39. Polymerization • Polymers – (many parts) organic compounds made up of chains of smaller units covalently bonded together • The formation of these large polymer molecules is called polymerization Synthetic Plastics (nylon, rayon, polyethylene, etc..) are polymers

40. Two Types of Polymerization Reactions 1. Addition Polymerization - involves the joining of monomers of unsaturated compounds • An addition reaction is one in which two or more molecules (monomers) join together to give a single product. Thousands of monomers join together to make polymers. (n-is usually used to represent huge numbers)

41. 2. Condensation Polymerization - result from the bonding of monomers(Single part) by removing water from hydroxyl groups and joining the monomers. +H2OH

42. Addition Reactions • Addition Reactions involve a double or triple bonds. C2H4 + Cl2 C2H4Cl2 or C2H4 + H2 C2H6 or Note: halides attach to different carbons

43. Substitution • involves the replacement of one or more of the hydrogen atoms in a saturated hydrocarbon with another atom or group. Halides do not need to attach to the same carbons

44. Fermentation • Fermentation is a chemical process in which yeast cell secrete enzymes (zymase) and break sugar chains into carbon dioxide and water. It creates alcohol. Zymase C6H12O6  2C2H5OH + 2CO2

45. Combustion (Complete) • Hydrocarbons react with oxygen to form CO2 and H2O • C3H8 + O2 H2O + CO2 Balance

46. C3H8 + 5O2 4H2O + 3CO2