Chapter 7 – Carbon Chemistry Section 1 – Chemical Bonding, Carbon Style

They are carbon (C) containing compounds. 90% of all compounds contain C. More than ten million compounds of carbon are now known. Organic compounds were alive at some point, like petroleum, crude oil, and coal. What are organic compounds?

Organic chemistry is the study of C. Inorganic chemistry is the study of non-carbon.

Why can carbon form a huge variety of different compounds? Carbon has 4 valence electrons that can form chemical bonds. Carbon atoms usually share electrons to form 4 covalent bonds. C can form single, double, or triple covalent bonds with other carbon atoms.

The C atoms can bond in straight chains, chains with branches, or form rings

* Compounds with only 2 or 3 C make straight chains. * Compounds with 4 or more C can make branched arrangements.

C can form bonds with other elements too.

Three (3) different forms of pure carbon: 1.Diamond The hardest mineral. Diamond crystals form deep within Earth at high temperature and pressure. Each C atom is bonded strongly to 4 other C atoms. Melting point = 3500 o C Used in cutting tools.

2.Graphite The lead in your pencil. Each C atom is bonded tightly to 3 other C atoms in flat layers. Bonds between atoms in different layers are weak, so layers can slide. Used as a lubricant in machines.

3. Fullerene (Buckminsterfullerene) Man-made in C atoms arranged in a repeating pattern similar to that of a soccer ball. Fullerenes have a ball-shaped open area. Future use: they may be used to carry medicine through the body or store very tiny computer circuits.

CARBON (C) - Element commonly found in meteorites, it occurs in several structural forms (polymorphs). All polymorphs are shown above (those starred have been found in meteorites and impact structures): a.diamond*;b. graphite*;c. lonsdalite*; d. buckminsterfullerene* (C60);e. C540; f. C70;g. amorphous carbon; h. carbon nanotube*.

Chapter 7 – Carbon Chemistry Sec. 2 – Carbon Compounds

Hydrocarbons Simplest organic compounds made of only C and H Properties determined by # if C and arrangement of atoms Form carbon chains that maybe straight branched or ring shaped

Examples of hydrocarbons: NameMolecular Formula Structural Formula Use Methane CH 4 Natural gas in heating homes Ethane C2H6C2H6 In extremely low temp refrigerators Propane C3H8C3H8 In gas grills & hot-air balloons Butane & Isobutane C 4 H 10 Fuel in most lighters

Properties of Hydrocarbons: * Flammable * Mix poorly with water (nonpolar) * Release energy when burned Molecular Formula – ex. CH 4 shows symbols of elements in a compound + number of atoms of each element. Isomers compounds with the same molecular formula but different structural formulas. Ex. Butane and Isobutane Structural Formula – ex. shows kind, #, and arrangement of atoms.

Isomers -- same molecular formula, different structural formula isobutane (C 4 H 10 )

Sometimes, chemists use different types of formulas to represent the same compound. The structural formula, condensed structure, backbone structure, and line structure of octane, a compound with the molecular formula C 8 H 18 appear as follows:

Saturated Hydrocarbons Have only single bonds Have the maximum # of Hydrogens Unsaturated Hydrocarbons Have double or triple bonds Have fewer H atoms for each carbon

Naming hydrocarbons Prefixes: 1 – meth 2 – eth 3 – prop 4 – but 5 – pent 6 – hex 7 – Sept 8 – oct Suffixes: - ane = Saturated (single bonds) - ene or -yne = Unsaturated Ethylene

Substituted Hydrocarbons Occurs when atoms of other elements replace one or more hydrogen atoms (O, N, S, halogen group, -OH, or –COOH ) Alcohols -Hydroxyl group (-OH) replaces a Hydrogen atom -Ex. CH 4 (methane) changes to CH 3 OH (methanol) which is used to make plastic and defrost airplanes. ORGANIC ACIDS - carboxyl group (-COOH) replaces a hydrogen. In many foods. Ex. CH 4 changes to CH 3 COOH (acetic acid.)

ESTERS An alcohol + an organic acid = Ester. Most have a sweet fruity, taste or smell. Used in pop, candies, and artificial flavors.

Polymers: Large molecules made many smaller molecules linked together forming chains The small links that make up the polymers are called monomers. Some polymers are from living things, like wool, cotton, silk, and others are synthetics, like polyester.