Unit B- Organic Chemistry

What is an Organic Compound? (3)

• A molecular compound containing carbon with the exception of CO2, carbonates, carbides and cyanides

• due to carbons 4 valence electrons, it makes it the backbone of many complex molecular compounds, often creating long chains and crystal structure

• the ability to make long chains make carbon the building block of all life on earth, “carbon based lifeform”

Common uses of fossil fuels (hydrocarbons)

Coal, Oil, and Natural Gas

Alkane Definition

A saturated Hydrocarbon with any single covalent bonds between its carbon atoms

Hydrocarbon Deffinition:

An atom containing only carbon and hydrogen atoms

What is the general formula for alkanes?

CₙH₂ₙ₊₂

Cyclic Alkanes:

A hydrocarbon in which the main structure consists of a chain of carbon atoms joined to form a closed ring

Orientations of Alkanes

Straight Chain Alkane

Cyclic Alkane

Alkyl Groups (3)

• An alkyl group is a type of substituent group

• One or more carbon atoms that form a branch off the main chain of a hydrocarbon.

• Alkyl groups are named with the prefix indicating the number of carbons atoms in the branch, like in your table, however you add a -yl suffix.

Substituent Group

an atom or group that replaces hydrogen in an organic molecule.

Structural Isomerism (2)

• Most hydrocarbons with 4 or more carbon atoms exhibit structural isomerism.

• Structural isomerism occurs when 2 molecules each have the same number and types of atoms but these atoms are bonded in different ways.

Naming Alkanes (1-20)

1 - methane

2 - ethane

3 - propane

4 - butane

5 - pentane

6 - hexane

7 - heptane

8 - ocatne

9 - nonane

10 - decane

11 - undecane

12 - dodecane

13 - tridecane

14 - tetradecane

15 - pentadecane

16 - hexadecane

17 - heptadecane

18 - octadecane

19 - nondecane

20 - Icosane 

Uncommon Alkyl Groups + Alhpa priority 

• Isopropyl, butyl isobutyl, sec-butyl, tert-butyl

• (ensure these are not apart of the longest carbon chain  

• chose “i” for iso alpha priority 

• for tert/sec-butyl, ignore the prefix and focus of butyl for alpha priority 

iso means

same number

Alkyl Halides + How to name (4)

• An alkane in which one or more hydrogen atoms have been

• substituted with one or more halogen atoms.

• Halides - implies halogen

• Add the root of the halogen followed by o when naming

Does the di, tri, tetra change alpha priority?

No you ignore it, ex if u have dimethyl and ethyl, ethyl still comes first

Unsaturated Hydrocarbon:

An unsaturated hydrocarbon is an organic compound, consisting of a carbon and hydrogen, with one more double or triple bonds joining pairs of carbon atoms within the molecules.

Alkene (2)

• a hydrocarbon with at least one carbon-carbon double bond

• CnH2n

Alkyne (2)

• a hydrocarbon that contains at least one carbon-carbon triple bond

• CnH2n-2

• Alkynes are linear

Naming Alkenes (3)

• you have to include alkenes in your parent chain, even if it is not the longest possible change

• Alkenes follow the same naming scheme as alkanes, except their ending is changed to “ene” instead of “ane”.

• Methene isn’t included as we need a minimum of 2 carbons

Pi bond:

Double bond

2,3,4 pi bond:

di, tri, tetra

Stereoisomers

Molecules that have the same chemical formula and structural backbone, but with a different arrangement of atoms in space

Cis isomer

A stereoisomer in which the groups of interest are located on the same side of a double bond

Trans isomer

a stereoisomer in which groups of interest are located on opposite sides of a double bond

Limitations of Cis/Trans

The cis and trans naming system is limited to simple molecules containing only 1 cis/trans group.

When and when not to include the a in: Pent-3-ene or penta-3-ene etc

Standard: no a pent-3-ene

When you have diene triene etc

Penta-3-diene or penta-3-triene

Why are Alkynes are linear + cis/trans isomers

because carbons only can have 4 bonds. If 3 are already attached to the triple bond, that leaves only 1 single bond to be used on it’s other side.

Alkynes alone do not form cis/trans isomers