Organic Chemistry

Organic Chemistry Topic 11 Review Book Tables P, Q and R

What is Organic Chemistry? • study of carbon and the compounds that it forms • carbon has 4 valence electrons so it will form 4 covalent bonds- lends itself to a great variety of compounds • May also contain but are not limited to the following elements: • Oxygen e) Phosphorus • Nitrogen f) Sulfur • Fluorine g) hydrogen • Bromine

Properties of Organic Compounds • Covalent bonds • generally nonpolar- what does that mean? • insoluble in water • low mp’s and bp’s: boiling point is directly related to the length of carbon chain • nonelectrolytes • slow to react because of the covalent bonds – many reactions require a catalyst • Hundreds of thousands of organic compounds because C can form so many bonds

Quick Review • How many valence electrons does an atom of carbon have? • How many bonds can an atom of carbon make?

Types of Organic Formulas • Molecular – how many atoms and what elements are in a molecule. Ex. C3H8 • Structural Formula – shows how the atoms in the molecule are bonded, Ex. C3H8 • Condensed Structural Formula – emphasizes groups of the atoms in the molecule Ex 1. CH3CH2CH3

Draw a Lewis structure for CH4 • Draw C2H6 Draw C6H14

Hydrocarbons (Tables P and Q) • molecules that contain only carbon and hydrogen • May have single, double or triple bonds • May form straight chains, branched chains or rings • homologous series  different groups of hydrocarbons • each group contains molecules that have similar structures and properties • as the molecular mass increases, the boiling point increases (why?)

1. Alkanes • Only single bonds • Saturated • the general formula is CnH2n+2 • End in –ane • Prefix tells you the number of carbon atoms • Example: Methane, Ethane, Propane, etc • May be straight or branched chains

2. Alkenes • One double bond (C = C) rest are single • Unsaturated • The general formula is CnH2n • First member is ethene Examples: Propene, Butene, Pentene • May be straight or • branched chains

3. Alkynes • one triple bond, the rest are single • unsaturated • the general formula is CnH2n-2 • First member is ethyne Example: Propyne, Butyne, Pentyne May be straight or branched

Aromatic Hydrocarbons • Made up of a chain of hydrocarbons that form a ring • Most common one is benzene • C6H6 in a ring of alternating double And single bonds

Saturated vs Unsaturated • Saturated hydrocarbons have ________________ • Unsaturated hydrocarbons have ______________ • Many hydrocarbons have isomers

Isomers • Isomers - molecules that have the same molecular formula but a different structural formula • Isomers of hydrocarbons differ in the length of the carbon chain or the position of a double or triple bond • Ex. C4H10 is an alkane that has 2 isomers • They will have different properties

Using Table P • 1. How many carbon atoms are in each hydrocarbon? •  a) methane ____ f) hexane ____ k) decane ____ •  b) ethane ____ g) ethyne ____ l) butyne ____ •  c) ethene ____ h) propane ____ m) butene ____ •  d) pentane ____ i) heptane ____ n) propyne ____ •  e) propane ____ j) octene ____ o) butane ____

Using Table P and Q • Compound  # of Carbons  SERIES  General FORMULA • Ex: Butane  4  Alkanes C4H10 • a) methane  ___________  _________ ___________ • b) butene  ___________  _________ ____________ • c) propyne  ___________  _________ ____________ • d) pentane  ___________  _________ ____________ • e) octane   ___________  _________ ____________ • f) heptene  ___________  _________ ____________ • g) propene   ___________  _________ ____________

Naming and Drawing Straight Chain Alkanes Without Branches • identify the number of carbons • use table P to get the prefix for that number • add the suffix “ane” • Ex: CH4= “meth” + “ane” = methane • ethane • propane • Butane • Pentane • Hexane • octane

Naming and Drawing Straight Chain Alkenes Alkenes without branches • Name alkenes the same way you would alkanes, EXCEPT you must specify the location of the double bond by using the lower number of the two that it is in between Examples: Ethene Propene Butene (1 Butene, 2 Butene) Pentene (1 Pentene, 2 Pentene,)

Naming and Drawing Alkynes • The rules for naming alkynes are the same for alkenes, except there is a triplebond instead of a double bond • 2-butyne • 2-hexyne • 3 hexyne • 1 pentyne • 3 octyne

Naming and Drawing Branched Alkanes You need to be able to identify three things: Parent chain, branch name, location Example 1. Identify the longest continuous chain (parent chain)- use table P for the prefix and add -ane 2. Find the branches 3. Number the carbons in the parent chain, starting at the side closest to the branch 4. Count the number of carbon atoms in the branch and get the prefix from Table P and add the suffix –yl 5. Use the number of the parent carbon atom, the name of the side chains and the name of the parent chain • 4 ethyl octane

Naming Branched Alkanes • If the same group occurs more than once as a side chain, you indicate this using prefixes (ex: di, tri). Indicate the positions of each group with a number • If the side chains are different, name the one with the smallest carbon number first • 2,3 dimethyl pentane

Naming and Drawing Branched Alkenes and Alkynes Branched Alkenes and Alkynes • follow the same rules for naming branched alkanes, EXCEPT when numbering the carbons, start with the side closest to the double bond or triple bond rather than the nearest side chain

Functional Groups – Replacement of One or More H • Other types of organic compounds can form when different atoms replace one or more of the hydrogens • happens to alkanes • These atoms or groups of atoms are called functional groups • They give the compound specific physical and chemical properties

1. Halides • When one of the halogens (F, Cl, Br, I) replaces a hydrogen atom • called a halide or a halocarbon • The functional group is the halogen • Naming: Specify the location of the halogen and use the following prefixes: chloro, fluoro, bromo, iodo • Uses: Teflon, Freon, CFC’s, dry cleaning solvents, pesticides

2. Alcohols • a hydrogen on an alkane is replaced with an -OH group (hydroxyl group- NOT hydroxide ion!) • the functional group is –OH • Classified according to the number of carbons bonded to the carbon where the –OH is • Primary, secondary, tertiary • Naming: Drop the “e” and add “ol”; specify the location of the –OH • Uses: fuel, solvents, industrial feedstock (used to make other products, such as formaldehyde, etc)

3. Ethers • The functional group is -O- • Naming: you name the left group and the right group and you follow it by the word ether • if both group are the same, use "di“ • Used to be used as anesthetics

4. Aldehydes • contain a carbonyl (C=O) group on an end carbon • No numbering • Naming: Drop the “e” and add “al”

5. Ketones • Carbonyl group on any carbon atom except the end ones • Formed by the oxidation of a secondary alcohol • Naming: drop the “e” and add “one”, specify the location

6. Organic Acids • The functional group is -COOH which is called a carboxyl group • Usually formed by oxidizing alcohols • Carboxyl groups are only attached to end carbons, so no numbering is needed • Naming: drop the “e” and add “oic acid”

7. Esters • They are formed from a reaction between a carboxylic acid and an alcohol • Naming: The name of the alcohol is given first, with the suffix changed to “yl” • Then the name of the acid is given with the suffix changed to “oate”

8. Amines • The functional group is -NH2 • called an amino group • Naming: drop the “e” and adding “amine”, specify location 9. Amides • They contain an amino group attached to the carbon atom of a carbonyl group • Naming: drop the “e” and add “amide”

1. Substitution • replacement of one or more hydrogen atoms in an alkane with another atom or group • ex. halogen atoms replace a hydrogen atom on an alkane to make a halide and an acid • ex. C2H6 + Cl2 C2H5Cl + HCl

2. Addition • involves adding one or more atoms at the site of a double or triple bond • occurs in alkenes or alkynes • Ex. C2H4 + Cl2 C2H4Cl2

3. Hydrogenation • type of addition • it is the addition of hydrogen to an unsaturated compound to make it saturated • it requires a catalyst and a raised temp • Ex. C2H4 + H2  C2H6

4. Esterification • the reaction of an organic acid with an alcohol to produce an ester plus water • slow reaction that is reversible • usually have pleasant odors

5. Saponification • when an ester (fat) reacts with an inorganic base (NaOH) to produce an alcohol and a soap

6. Polymerization • the formation of large molecules called polymers by combining smaller units called monomers • used to make plastics and rubber, proteins, starches and cellulose • Condensation polymerization: the bonding of monomers by a dehydration reaction • ex. glucose + glucose  sucrose + water • Addition polymerization: the joining of monomers by eliminating double or triple bonds • Ex. ethene + ethene = butane

7. Fermentation • when yeast breaks down 6-carbon sugars to produce carbon dioxide and an alcohol • ex. C6H12O6 2C2H5OH + CO2

8. Combustion (and so...we end as we began) • When a saturated hydrocarbon reacts with oxygen to produce water and carbon dioxide • A lot of energy (heat) is given off • C3H6 +5O2 3CO2 + 4H2O

Lastly… • Practice your regents exams • Use the Barron’s book • Bring a NON-GRAPHING calculator, a black pen and pencil (for drawing) to the Regents Exam Have a great summer and come back to visit next year!

Organic Chemistry