Organic Chemistry

• The chemistry of carbon compounds. • Carbon has 4 valence electrons which

gives it the ability to form complex chains, branched chains and rings.

• As a result of this property, large biomolecules such as proteins, lipids, carbohydrates, and nucleic acids can be formed.

Organic compounds come in many shapes:

• Chains

• Branched chains

• Rings Ring-shaped hydrocarbons are called cyclic hydrocarbons. To name these compounds, add “cyclo” before the name.

The molecule above is cyclohexane.

Hydrocarbon prefix # of carbon atoms name formula structure*

Meth 1 methane CH4

Eth 2 ethane C2H6

Prop 3 propane C3H8

But 4 Butane C4H10

Pent 5 pentane C5H12

Hex 6 hexane C6H14

Hept 7 heptane C7H16

Oct 8 octane C8H18

Non 9 nonane C9H20

Dec 10 decane C10H22

Functional Groups -Most organic compounds have other groups of atoms

attached to the hydrocarbon. -These groups are called functional groups because

they are the chemically functional part of the compound. Most of organic chemistry deals with these functional groups and their reactions.

Functional Groups to memorize. Alcohols -OH C2H5OH (Ethanol) Halocarbon (Halogen Hydrocarbon) R-Cl, F, I, Br CH3Cl (Chloromethane)

Alcohols

• OH is substituted for an H atom. H H H H—C---C---C—OH Propyl Alcohol (propanol) H H H • Same naming convention as alkanes -Prefix showing number of Carbons -End with anol or yl plus the word alcohol. e.g. ethanol or ethyl alcohol.

Polymers

A polymer is a large molecule formed by the covalent bonding of repeating small molecules. The small repeating molecules are called monomers.

Formulas

• Lewis structures of alkanes look like this. • Also called structural formulas.

Properties of Alkanes

What happens to the boiling point as you increase the number of carbon atoms?

Hydrocarbon prefix

# of carbon atoms

name formula Alcohol-OH Halocarbon-Cl

Meth 1 methane CH4 methanol CH3OH

Chloromethane CH3Cl

Eth 2 ethane C2H6 ethanol C2H5OH

Chloroethane C2H5Cl

Prop 3 propane C3H8 propanol

chloropropane

But 4 Butane C4H10 butanol

Chlorobutane

Pent 5 pentane C5H12 pentanol Chloropentane

Practice Problems

Name Chemical Formula Type

Ethane Alkane

C8H18

Ethanol Alcohol

Fluoromethane Halocarbon

Cyclopentane

Hexanol

Practice Problems

Name Chemical Formula Type

Ethane C2H6 Alkane

Octane C8H18 Alkane

Ethanol C2H5OH Alcohol

Fluoromethane CH3F Halocarbon

Cyclopentane C5H10 Cyclic Alkane

Hexanol C6H13OH Alcohol

Monomers Polymers Mono = 1 Poly = many

Chapter 25 HW – Du 5/23 Do on blank sheet of paper to be attached to flipbook. • Define: Hydrocarbons, Alkanes, Alkyl Group, Saturated vs. Unsaturated

Compounds, Structural Isomers, Cyclic Hydrocarbons, Fossil Fuels, Cracking

• Read: Pages 743 – 754 + 762 - 766 • Answer:

– Questions 7, 8 and 10 on page 751 – Question 11 on page 753 – Draw two isomers of butane [See page 754] – Questions 24 & 26 on page 765 – What are octane numbers and what do they have to do with fuel quality?

[Page 766] – What type of alkanes (straight versus branched) are more prone to causing

engine knock? [Page 766] – Compare heptane and isooctane in terms of engine knock. [Page 766] – How are fuels rated now? Use motor octane rating and research octane rating

in your answer. [Page 766]