Unit 17: Organic Chemistry

 Name given to the study of carbon and carbon compounds.  Living things contain many organic compounds. Products of living things, such as petroleum, wood and coal supply the raw materials from which organic chemicals are obtained.

I. Characteristics of Organic Compounds

A. Organic compounds are generally nonpolar in nature. (symmetrical charge distribution)

B. Only a few are soluble in water. (These include ethanoic acid, various sugars and some alcohols)

C. Organic compounds are generally nonelectrolytes; they do not ionize well

and as a result are poor conductors of electricity.

D. Due to weak intermolecular forces of attractions, organic compounds usually have

low melting points.

E. Reaction rates of organic compounds tend to be slower than those of inorganic compounds. The bonding within the organic molecules itself

(intramolecular as opposed to intermolecular forces) are covalent and very strongly held together.

II. Bonding:

A. Carbon has 4 valence electrons. Due to the hybridization of these

valence sublevels, carbon has 4 sites for bonds, forming a tetrahedral structure. B.Structural formulas are often used to represent the molecule:

Ex: Methane CH4

C. Isomers: compounds with the same molecular formula, but different

structures, so different properties

Ex: C5H12

D. Carbon can bond with a second carbon by sharing

__ 1 _____ pair(s) of electrons (single bond)

___ 2 _____ pair(s) of electrons ( double bond)

___ 3 _____ pair(s) of electrons ( triple bond)

III. Hydrocarbons: organic compounds containing only H and C

A. Homologous Series: a group of organic compounds with similar properties and related structures (each successive number increases by 1 carbon and 2 hydrogens) Table Q

Alkanes: CnH2n+2 Alkynes: CnH2n-2

Alkenes: CnH2n Benzenes: CnH2n-6

1. To name these compounds, you use prefixes dependents upon the number of carbons present in the substance. TABLE P

B. Aliphatic Compounds (Compounds that are aligned in a straight chain)

1. Alkanes: CnH2n+2

All C to C bonds are single . This compound is said to be saturated -has the max # of H around each C

possible

To name alkanes: Use the prefix + -ane # of carbons name molecular formula structural formula

1 methane CH4

2 ethane

2. Alkenes: CnH2n

Hydrocarbons containing one double carbon to carbon bond.

Because of the double bond they are said to be unsaturated (they have less hydrogen atoms than do saturated compounds with the same number of carbons) *Cannot have a 1 carbon alkene* To name alkenes: use prefix + -ene # of carbons name molecular formula structural formula 1 *cannot have – you need 2 carbons for the double bond

2 ethene C2H4

 If the double bond is not on an end carbon, the name of the alkene will change as follows:

Number the carbons from the end of each side…then use the smallest number to tell where the double bond is located.

3. Alkynes: CnH2n-2

. unsaturated hydrocarbons with one triple carbon to carbon bond.

To name alkynes: use the prefix + -yne # of carbons name molecular formula structural formula 1 *cannot have – you need 2 carbons for the triple bond 2 ethyne

4  If the triple bond is not on an end carbon, the name of the alkyne will change as follows:

Number the carbons from the end of each side…then use the smallest number to tell where the triple bond is located.

C. Aromatic Hydrocarbons: closed chain (ring chain) structures that are often unsaturated with alternating double and single bonds.

1. The Benzene Family: CnH2n-6 *you should know the following two*

a. Benzene: C6H6

b. Toluene: C7H8 IV. Functional Groups: an atom (ion) or group of atoms polyatomic ion) responsible

for specific properties and characteristics of organic

compounds Table R

V. Other Organic Compounds:

A. Organic Alcohols: General Formula R-OH

1.Monohydroxyl alcohol:

a. contains one -OH group(s)

b. to name: use alkane name, drop the e and add –ol

c. most alcohols are monohydroxyl

Example: Structure Molecular Formula Name

1a. Primary Alcohol: one with the –OH group attached to an end carbon (attached to a carbon that is attached to only one other carbon) ex:

1b. Secondary Alcohol: one with the –OH group attached to a carbon that is attached to two other carbons ex:

To name a secondary alcohol, you must name the longest carbon chain and everything that is attached to that chain is named as you would name the alkenes and alkynes. Ex: 1c. Tertiary Alcohol: one with the –Oh group attached to a carbon that is attached to three other carbons. Ex:

*name the same way you would name secondary alcohols!

2. Dihydroxyl Alcohols:

a. contains two -OH group(s)

b. to name: use alkane name, drop the e and add –diol *also include the carbon #’s the –OH groups are attached to.

c. you should know: C2H4(OH)2 Structure Stock Name Common Name

3. Trihydroxyl Alcohols

a. contains three -OH group(s)

b. to name: use alkane name, drop the e and add –triol *also, name the carbon #’s the –OH groups are attached to.

c. you should know: C3H5(OH)3 Structure Stock Name Common Name B.Organic Acids (Carboxylic Acids) *weak electrolytes*

 The only organic electrolytes

1. General Formula: R-COOH or R-C-O-H

a. to name: use alkane name, drop the e and add –oic acid

Molecular Formula Structure Name 1

C. Aldehydes:

1. General Formula R-CHO or R-C-H

a. to name: use the alkane name, drop the e and add -al

Molecular Formula Structure Name 1

**be careful, name is close to alcohol name!!! D. Ketones:

1. General Formula R-C-R

a. to name: use the alkane name, drop the e and add –one, also name the # of the carbon containing the =O Molecular Formula Structure Name

E.Esters: The product of a combination reaction between an acid and an alcohol.

1. General Formula R-COOR’ or R-C-O-R’

a. to name: use the beginning of the alcohol name and the ending of the acid name. Change the acid name by dropping –ic and adding –ate.

Molecular Formula Structure Name

F. Ethers:

1. General Formula R-O-R’

a. to name: name the groups attached to the –O- Molecular Formula Structure Name *Diethyl ether is commonly used as a solvent and anesthetic*

G. Halides: alkanes with halogens attached, either by addition or substitution reactions.

1. General Formula R-X where X is any halogen

a. to name: use the carbon # the halogen is attached to, then the prefix of the halogen, then the alkane (or alkene) name.

Halogen Prefixes: F fluoro Cl chloro Br bromo I iodo

H. Amines:

1. General Formula R-NH2; functional group –NH2

a. to name: drop the e off the alkane name, add -amine

Molecular Formula Structure Name I. Amino Acids: the building blocks of proteins, they are the combination of acids and amines.

1. Simple amino acids are named using the IUPAC system, but most are complex and common names are used.

Example:

J. Amides: the combination of an amine and an aldehyde

1. General Formula R-C-NH2

a. to name: drop the e from the alkane name and add -amide

VI. Organic Reactions:

 Generally very slow in nature  Usually only the functional group is involved

A. Substitution Reactions: only saturated hydrocarbons undergo substitution reactions.

Process by which an H on an alkane is replaced by

another substance (usually a halogen) Start with 2 reactants end with 2 products (alkane + something) Example:

B. Addition Reactions: only unsaturated hydrocarbons undergo addition reactions.

Process by which an alkene or alkyne react with something (such as a halogen) to break the double or triple bond and add a substance on.

Start with 2 reactants end with 1 product (alkene/alkyne + something) Example:

Remember how to name the products of substitution and addition reactions, these are your Halides. Examples:

C. Fermentation: Process by which enzymes (usually produced in living organisms) catalyze the breakdown of large organic molecules to produce alcohol and

*usually yeast is involved, the enzymes produced by these yeasts act as a catalyst for the breakdown of organic molecules.

Example: .

D. Esterification:

Process by which an organic acid and alcohol react to

produce an ester and H2O *dehydration synthesis

*condensation reactions

Organic acid + alcohol = ester + water

E. Saponification: Process by which fats are hydrolyzed by strong

bases to produce soap and glycerol

Example:

F. Polymerization:

Process by which a larger molecule (polymer) is

made from smaller, repeating units.

Polymer: a compound with a high molecular mass made up of smaller subunits (monomers)

that have been bonded together.

Types of polymers: Natural: proteins, starch, cellulose Synthetic: polyester, polyurethane, plastics, rubber, nylon, styrofoam General Reaction:

nC2H4 = (-C2H4-)n

Types of Polymerization Reactions:

1. Condensation polymerization: releases water

2. Addition polymerization: breaks double or triple bonds G. Oxidation by Aldehydes:

Process by which an aldehyde reacts with oxygen to

produce an acid

Example:

H. Combustion:

Process by which saturated hydrocarbons react with oxygen (are burned) to produce carbon dioxide,

water and heat.

*usually considered the burning of fossil fuels