Intro to organic chemsitry

Define empirical formula

Simplest whole number ratio of atoms in a molecule

Define molecular formula

The actual number of atoms of different elements in a molecule

How do you calculate molecular formula?

1. Mass of empirical formula

2. Find MF:EF ratio by doing Mr of ef/mass of ef

3. Multiply EF by the ratio to scale up

How do you calculate empirical formula?

1. Find the mass/percentage of all atoms

2. Find moles of all atoms

3. Divide by smallest number of moles

4. Use mole ratio to write EF

Define displayed formula

Shows every atom and every bond in a molecule

Define structural formula

Shows arrangement of atoms in a molecule without showing every bond

Define skeletal formula

Shows the bonds of the carbon skeleton only. Carbon and hydrogen atoms not shown but functional groups are

Give the suffix and general formula for no double bonds

-ane

CnH2n+2

Give the suffix, general formula and functional group for at least one double bond

-ene

CnH2n

C=C

Give the suffix, general formula and functional group for an alcohol

• -ol

• CnH2n+1OH

• R-OH

Give the suffix, general formula and functional group for an aldehyde

• -al

• CnH2nO

• R-CHO

Give the suffix, general formula and functional group for a ketone

• -one

• CnH2nO

• R-CO-R’

Give the suffix, general formula and functional group for a carboxylic acid

• -oic acid

• CnH2n+1COOH

• R-COOH

What’s a homologous series?

A family of compounds with the same functional group and general formula but different chain lengths

What is a functional group?

An atom or group of atoms responsible for characteristics/reactivity

What’s the order of priority according to IUPAC?

1. Carboxylic acids

2. Nitriles

3. Aldehyde

4. Ketones

5. Alcohols

6. Amines

7. Alkenes

8. Alkanes

9. Halides

What is structural isomerism?

When molecules have the same molecular formula but different structural formula

What are the 3 types of structural isomerism?

1. Chain

2. Position

3. Functional group

What is chain isomerism?

The carbon chains are organised differently

What is positional isomerism?

The functional group is attached to the main chain in a different location

What is functional group isomerism?

The atoms are reorganised to give a different functional group

What is stereoisomerism?

When molecules have the same structural and molecular formula but have different spacial arrangements

What are the 2 types of stereoisomeism?

1. E/Z (geometric)

2. Optical

What are the 2 reasons why E/Z isomerism occurs?

1. Restricted movement around planar C=C

2. 2 different groups on each carbon in the double bond

How are E/Z isomers decided?

If the 2 substituents with the highest atomic number are on the same side of the double bond, it is a Z isomer

If they are on different sides, it is an E isomer

(If there’s a tie in atomic number, go to the next atom along the chain)

What is the general polarity trend for E/Z isomers?

Z-isomers are more polar as the polar groups are close together and the dipoles add up

E-isomers are less/not polar as the polar bonds cancel out