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Organic Chemistry

study of carbon to carbon

compounds

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Bonding of carbon atoms Carbon has 4 valence electrons

Can bond with up to 4 elements at once to achieve an octet in the shape of a tetrahedron

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Carbon atoms share electrons in covalent bonds to form molecules

1. single bond - One pair of e- shared between C’s, saturated) between carbon (C-C-C-C)

2. double bond – Two pair of e- shared between 2 C’s, unsaturated) (C=C-C-C)

3. triple bond - Three pair of e- shared between 2 C’s, unsaturated) ( C C-C-C)

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Can form chains of unlimited length, variety and complexity

CH3

CH2CH2

CH2CH2

CH2CH2

CH2CH2

CH3

C

CO

C

C

Cl

HH

H

Chains can be:

open (aliphatic) or branched

•closed (ring or cyclo)

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ORGANIC PROPERTIES • Covalently bonded substances• Low melting points due to weak

IMF’s• Nonelectroytes- poor conductors

(except acids which are weak electrolytes)

• Generally non-polar and insoluble in water (soluble in non-polar substances)

• Slower reaction rates than inorganic compounds

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HYDROCARBONS

• Molecules composed only of carbon and hydrogen atoms.

• Homologous series: group of organic compounds with similar properties and related structures (differ by CH2)

Alkanes (single bond between C’s, saturated)

Alkenes (1 double bond between 2 C’s, unsaturated)

Alkynes (1 triple bond between 2 C’s,

unsaturated)

• Count the number of carbons and add the appropriate suffix!

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HydrocarbonsHydrocarbonsC C C C

C C

C

C

C

C

C

C

H

H

H

H

H

H

C C C C C

H

H

H

H

H H

H

H

H

H

H

H

Alkanes Alkenes

Alkynes Aromatics

C C C C C

H

H

H

H

H

H

H

H

H

H

C C C C CH

H

H

H

H

H

H

H

benzene

pentane pentene

pentyne

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Alkanes(CnH2n+2

)

•SATURATED and SINGLE Bonds (can’t be broken)•add SUFFIX –ane

• Examples CH4 = methane – natural gas C2H6 = ethane – natural gas C3H8 = propane – outdoor grills

•To find the number of hydrogens, double the number of carbons and add 2.

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Alkenes(CnH2n)

• UNSATURATED and DOUBLE bond• add suffix –ene • Examples

– C2H4 = Ethene– C3H6 = Propene– C4H8 = Butene

• To find the number of hydrogens, double the number of carbons.

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Alkynes

(CnH2n-2)

• UNSATURATED and TRIPLE bond• add suffix –yne• Examples:

– C2H2 = Ethyne

– C3H4 = Propyne

– C4H6 = Butyne

• To find the number of hydrogens, double the number of carbons and subtract 2 hydrogen.

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Expressing Formulas

ethane propane

Molecular formula (tells how many units of each atoms are present)

C2H6 C3H8

STRUCTURAL FORMULA(shows bonding pattern & shape)

H H

H C C H

H H

H H H

H C C C H

H H H

Condensed FormulaCH3CH3 CH3CH2CH3

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This is 1-butene, because the double bond is between the 1st and 2nd carbon from the end.

This is 2-butene. The double bond is between the 2nd and 3rd carbon from the end.

ISOMERS - Molecules that share the same molecular formula, but have different structural formulas.

• Different chemical and physical properties• The more carbon atoms, the more isomers possible

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Substituted Hydrocarbons• Hydrocarbon chains can have three kinds of

“dingly-danglies” attached to the chain. If the dingly-dangly is made of anything other than hydrogen and carbon, the molecule ceases to be a hydrocarbon and becomes another type of organic molecule.

– Alkyl groups– Halide groups– Other functional groups

• To name a hydrocarbon with an attached group, determine which carbon (use lowest possible number value) the group is attached to. Use di- for 2 groups, tri- for three.

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Naming Hydrocarbons with substitutions

1. Pick the longest continuous chain of carbon atoms. This is called the parent chain. Number each C in the chain.

2. Determine which carbon (use lowest possible number value) the group is attached to.

3. If more than one of the same type of groups is attached to the parent chain, a prefix is used: di-, tri-, etc.

4. If two or more substitute groups are present, arrange alphabetically.

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“Branches” are classified as alkyl groups. Methyl Ethyl CH3 C2H5

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Halide Halide GroupsGroups

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Alcohol

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Location of hydroxylPRIMARY (1o): the functional group is bonded to a carbon that is on the end of the chain.

SECONDARY (2o): The functional group is bonded to a carbon in the middle of the chain.

TERTIARY (3o): The functional group is bonded to a carbon that is itself directly bonded to three other carbons.

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Di and Tri-hydroxy Alcohols

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Organic Acid

These are weak acids. The H on the right side is the one that ionized in water to form H3O+. The -COOH (carboxyl) functional group is always on a PRIMARY carbon.

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Aldehyde

Aldehydes have the CO (carbonyl) groups ALWAYS on a PRIMARY carbon. This is the only structural difference between aldehydes and ketones.

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Ketone

Ketones have the CO (carbonyl) groups ALWAYS on a SECONDARY carbon. This is the only structural difference between ketones and aldehydes.

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Ether

Ethers are made of two alkyl groups surrounding one oxygen atom. The ether is named for the alkyl groups on “ether” side of the oxygen.

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Ester

•Esters are named for the alcohol and organic acid that reacted by esterification to form the ester.

•Esters contain a COO (carbonyl) group in the middle of the molecule, which differentiates them from organic acids.

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Amine

- Component of amino acids, and therefore proteins, RNA and DNA…life itself!

- Essentially ammonia (NH3) with the hydrogen’s replaced by one or more hydrocarbon chains, hence the name “amine”!