Objectives

SWBAT Define an organic compound. Explain how the structure and bonding of

carbon lead to the diversity of organic compounds.

Distinguish among the structures of alkanes, alkenes, and alkynes.

Recognize characteristics of organic compounds such as alkanes.

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Introduction to Organic Chemistry

Organic Compounds

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Organic Compounds

Organic compound: Compound made from one or more C atoms

with many H atoms. May also contain O, S, N, and halogens.

Hydrocarbon = organic cpd with C & H. Saturated = all single bonds Unsaturated = multiple bonds

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Properties of Organic Compounds

Have low melting points and boiling points.

Are flammable. Are soluble in

nonpolar solvents therefore are not soluble in water. Oil (organic) and

water (inorganic)

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Organic vs. Inorganic

Propane, C3H8, is an organic compound used as a fuel.

NaCl, salt, is an inorganic compound composed of Na+ and Cl− ions.

Why is propane an

organic compound, but

NaCl is not?

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Why Carbon? (remember biology)

In carbon compounds Carbon has 4 valence electrons and hydrogen has 1.

• • C • H •

•

To achieve an octet, C forms four covalent bonds. H H

H C H H C H

H H CH4 , methane

Alkanes

Saturated hydrocarbon (only SINGLE bonds between adjacent carbon atoms).

Formula: CnH2n+2

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Names of Alkanes

The names of alkanes Use a prefix to indicate the number of carbons

in a chain. End in –ane.

Prefixes for hydrocarbons

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Structural Formulas for Alkanes

Alkanes are written with structural formulas that are

Expanded to show each bond. Condensed to show each carbon atom and its

attached hydrogen atoms. Expanded Condensed H

H C H CH4 , methane

H

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Learning Check

A. Write the condensed structural formula for:

H H H H H

H C C C C C H

H H H H H

B. What is its molecular formula?

C. What is its name?

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Learning Check

Write the condensed structural formula for

A. ethane

B. heptane

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Alkyl groups

Alkyl groups are Alkanes that are missing one H. Side groups attached to carbon chains. Named with a –yl ending. H

H C CH3 methyl H H H H C C CH3 CH2 ethyl H H

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Alkanes with Alkyl Groups

CH3

CH3 CH CH3 methylpropane

methyl groups

CH3 CH3

CH3 CH CH2 CH CH3 2,4-dimethylpentane

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Guide to Naming All Alkanes

Give the name of CH3 CH3

CH3─CH─CH─CH3

STEP 1 Longest chain is butane.

STEP 2 Number chain. CH3 CH3

CH3─CH─CH─CH3

1 2 3 4

STEP 3 Locate alkyl groups and name.

2,3-dimethylbutane

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Alkenes and Alkynes

Alkenes - unsaturated hydrocarbon with at least one double bond

CnH2n

Alkynes - unsaturated hydrocarbon with at least one triple bond.

CnH2n-2

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Naming Alkenes and Alkynes

• Use the same prefixes as you did for naming Alkanes.

• Replace “ane” with “ene” or “yne”

Rules for Naming Hydrocarbons

1. Find the longest continuous chain of carbon atoms. Use the proper prefix to name the chain. If it is an alkane add the ending –ane If it is an alkene add the ending –ene If it is an alkyne add the ending -yne

2. Number the carbon atoms in the chain so that the lowest possible numbers will be given for the attached side groups

3. Name the groups attached to the chain by adding a prefix –yl to the stem name. Locate them by identifying the number assigned to the carbon it is located on

4. If there is more than one group arrange them in alphabetical order

Halogen Substitution

A hydrogen can be replaced with Chloro -Cl Bromo-Br Iodo -I

Name using the lowest number carbon