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An Introduction to ORGANIC CHEMISTRY. Lesson 1. ORGANIC CHEMISTRY. The study of compounds which contain carbon-carbon and carbon-hydrogen bonds Organic compounds must have C-H bonds Carbon can form total of 4 covalent bonds can form double, triple or single bonds
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An Introduction to ORGANIC CHEMISTRY Lesson 1
ORGANIC CHEMISTRY • The study of compounds which contain carbon-carbon and carbon-hydrogen bonds • Organic compounds must have C-H bonds • Carbon • can form total of 4 covalent bonds • can form double, triple or single bonds • they can also form polar covalent bonds and compounds
RECALL… • Electronegativity is the measure of an atom’s pull on electrons • For example: δ+ C=O δ- • Shape determine overall polarity of molecules • Molecules that are symmetrical are NON POLAR • Molecules that are asymmetrical are POLAR • For example H O=C=O C Cl Cl Cl Symmetrical = Non Polar Asymmetrical = Polar
TYPES OF HYDROCARBONS • Hydrocarbons-contain hydrogen and carbon atoms • Can be • Aromatic • Aliphatic
AROMATIC HYDROCARBONS • contain aromatic benzene rings • Benzene = 6 carbon ring with 3 double bonds
ALIPHATIC HYDROCARBONS • contain C atoms bonded in chains or rings • Example: CH3-CH2-CH3 or
ALIPHATIC HYDROCARBONS (Chains) 1) Alkane – hydrocarbons that have onlysingle bonds Example: 2) Alkene- hydrocarbons with at least 1 double bond Example:
ALIPHATIC HYDROCARBONS (Chains) 3) Alkyne- hydrocarbon with at least 1 triple bond • Example:
ALIPHATIC HYDROCARBONS (Rings) 4) Cycloalkane- hydrocarbonsin a ring
REPRESENTING ORGANIC MOLECULES • Molecular formula: C2H6O • Expanded formula: CH3CH2OH • Structural Diagram: • Condensed structural diagram: CH3-CH2-OH • Line structural diagram:
NOMENCLATURE OF ORGANIC COMPOUNDS • IUPAC Rules- pg 13-14 Prefix + Root + Suffix Indicates the name and location of each branch of functionalgroup Tells you how many carbons are in the main chain Indicates the family
THE SUFFIX: • Indicates the family
PREFIX • What is attached to the main chain? • Indicates name and location of each branch and functional group on main carbon chain
Example 1 1 2 3 4 Longest chain has 4 carbons: Root is But Single bonds main chain (Alkane family) : Suffix is ane Name: but + ane butane
Example 2 Longest Chain has 3 carbons: Root = Prop Branching chain on carbon # 2 Prefix: 2-methyl Single Bonds main chain (Alkane): Suffix- ane 2-methylpropane
Example 3 Longest chain has 7 carbons: Root is Hept Branching chain on Carbon 3 Prefix: 3-methyl Single bonds main chain (Alkane) : Suffix is ane 3-methylheptane
Example 4 Longest chain has 6 Carbons: Root is Hex Two branching chains: 2 carbons (ethyl) & 1 carbon (methyl) Single bonds main chain (Alkane) Suffix: ane Use lowest numbering for the branching chain and place in alphabetic order 4-ethyl-2-methylhexane Prefixes
Example 5 Longest chain has 4 carbons: Root name: But One double bond in main chain (ALKENE) Suffix: ene Give the lowest number to the double bond 2- butene
Example 6 • Longest chain has 5 carbons: Root is pent • One double bond in main chain (Alkene) • suffix: -ene • Branching chain (1 carbon) at carbon 2 • Prefix is methyl 2-methyl-3-pentene
Example 7 1 2 3 4 5 6 7 • Longest chain has 7 carbons: Root is Hept • Two double bonds in main chain (Alkene) • Suffix: diene (because there are 2 double bonds) 2,5-heptediene
Example 8 • Longest chain has 7 carbons: Root is Hept • One double bond in main chain (Alkene) • suffix: -ene • Two branching chain with one carbon each (at C2 and C5): • Prefix is dimethyl 2,5-dimethyl-3-heptene
Example 9 4 3 5 2 1 • Number of carbons in ring is 5: Root name: pent • Single bonds in ring (alkane) • suffix: ane • Ring: cyclo cyclopentane
FYI • Numbers are always separated using commas Ex: 2,3 • Letters and numbers are always separated using dashes (-) Ex: 2-methyl • Ex: 2,3,3-trimethyloctane or 2,3- dimethyl-4-nonene
STRUCTURAL ISOMERS • molecules with same molecular formula but different molecular structure • Example: C2H6O
GEOMETRIC ISOMERS • Occur due to restricted rotation in a molecule. • C=C molecule cannot rotate around the double bond • Therefore different geometric isomers are formed. • Example: cis-2-butene trans-2-butene
FYI • trans isomer • from latin meaning "across" - as in transatlantic • cis isomer • from latin meaning "on this side"
GENERAL FORMULA Rfunctional group Example: CH3-CH2-OH R-alkyl group functional group alkyl group or main Carbon chain responsible for physical and chemical properties