Introduction to Organic Chemistry - 3.1

-definitions -functional groups -nomenclature -isomerism

what is empirical formula?

the simplest whole number ratio of atoms of each element in a compound

what is molecular formula?

the true number of atoms of each element in a compound

what is structural formula?

shows the arrangement of atoms in a simplified form, without showing all the bonds

what is displayed formula?

shows every single atom and every single bond in an organic compound

what is skeletal formula?

carbon atoms are not drawn

-carbon atoms are assumed to be where the lines meet

-hydrogen is not drawn but is assumed to be bonded to the carbon

what is a functional group?

an atom or group of atoms that determine the chemical properties of the molecule

ALKANES

-general formula

-functional group

CⁿH²ⁿ⁺²

C-C

ALKENES

-general formula

-functional group

CⁿH²ⁿ

C=C

HALOALKANES

-general formula

-functional group

CⁿH²ⁿ⁺¹X

-X

ALCOHOLS

-general formula

-functional group

CⁿH²ⁿ⁺¹OH

-OH

CARBOXYLIC ACIDS

-general formula

-functional group

CⁿH²ⁿO²

C=O—OH

ALDEHYDES

-general formula

-functional group

CⁿH²ⁿO

H

-C=O

KETONES

-general formula

-functional group

CⁿH²ⁿO

-C=O

what are structural isomers?

what are the different type of structural isomers?

have the same molecular formula but different structural formula

three types:

-chain

-position

-functional group

ALKYL

• any branch or side chain

• e.g → CH3 - methyl

  CH2CH3 - ethyl

  CH2CH2CH3

what is chain isomerism?

have the same functional group but different arrangement of the carbon skeleton → some are straight chained others are branched

what is position isomerism?

the same functional group but it is in a different position on the carbon chain

what is functional isomerism?

same atoms arranged into different functional groups

define stereoisomerism

isomers have the same structural formula but their atoms are arranged differently in space

one type of stereoisomerism is E/Z isomers in alkenes

what is the difference between e-isomers and z-isomers?

Z-isomers have the same group/atom above or below the double bond (zame side)

E-isomers have the same group/atom on different sides of the double bond (e=enemies ∴ opposite sides)

what is a homologous series?

a series of chemically similar compounds which conform to a general formula. Each member of a series differs by a CH₂ group. members of the group show a graduation in physical properties.

What is the CIP method?

briefly describe the CAHN, INGOLD, PRELOG (CIP) method

CIP priority rules are rules which determine whether a molecule is an E or a Z isomer.

1. compare atomic number of atoms directly attached to each side of the double bond ; atom of higher atomic number is given priority

2. if the atoms are both high priority and they are on the same side of the carbon bond it is the Z form.

• If both priority atoms are on the opposite side of carbon bond it is the E form