S3.2 CHEM

Types of formula

Molecular/Empirical/Full structural/Condensed structural/Skeletal

Stereochemical formula

Used to represent the 3D structure of an organic compound

Wedge tapered bond

A bond coming out of the plane of paper (aka towards the viewer)

A dashed bond

Represents a bod going into the paper

A straight line

bond in the same plane as the paper

Functional groups

is an atom/group of atoms that give an organic compound its physical/chemical properties

Homologous series

Family of compounds that can be grouped together based on similarities in their structure and reactivity.

Homologous series of alkanes (increasing C)

Methane/Ethane/Propane/Butane/Pentane/Hexane

Optical isomers

each of two or more forms of a compound which have the same structure but are mirror images of each other and typically differ in optical activity.

Chiral carbons

A carbon bonded to 4 different atoms or groups of atoms. AKA stereocentre or asymmetric centre

Optical isomerism

Molecules with one or more chiral carbon atoms exhibit a type of configurational isomerism called optical isomerism

enantiomers

a pair of optical isomers called enantiomers

Line bond

Aligned with the plane of the paper

Wedge bond

Comes out of the plane (towards the viewer)

Dash bond

Going behind the plane (away from the viewer)

Optical activity - ability to rotate plane-polarized light

a pair of enantiomers under the same conditions will rotate plane-polarized light by the same angle but opposite directions (clockwise & anti-clockwise)

Racemic Mixture

A 50:50 mixture of two enantiomers and does not polane-polarized light.

Mass spectrometry - fragmentation

Analytical technique that can be used to break up organic compounds into fragments and ions

Mass specturm

A graph of with the molecular masses of different fragments

Fragmentation pattern

Different peaks with a mass spectrum

Molecular ion peak

Parent compound, peak with the highest mass to charge ratio

Infrared IR spectroscopy

Analytical technique that can be used to identify the types of bonds present in an organic molecule and to determine its functional groups

Types of vibration: Stretching/compression and bending

Type of vibration depends on whether a molecule is diatomic or polyatomic

IR spectroscopy; factors affection frequency of vibration when molecules absorb radiation

1. Bond enthalpy

2. Masses of atoms in a bond