Chemistry s2.2 and s3.2

Alcohol

Hydroxyl functional group

-anol

CnH2n+1 OH

Alkane

Single carbon bond

-ane

Cn H 2n+2

Alkene

Double carbon bond

• ene ending

• Alkenyl functional group

• Cn

Alkyne

Triple carbon bond

-yne ending

Alkynyl functional group

Cn H 2n-2

Ether

Ether functional group

Isomer of alcohol

Oxyalkane ending

Aldehyde

Aldehyde/carbonyl functional group

Anal ending

Isomer of ketone

Ketone

Carbonyl functional group

Isomer of aldehyde

Anone ending

Carboxylic acid

Isomer of ester

Carboxyl functional group

Ends in anoic acid

CnH2n+1COOH

Ester

Isomer of carboxylic acid

Ester functional group

Ends in anoate

Amide

Nitrogen containing

Carboxyamide functional group

Ends in anamide

Amine

Nitrogen containing

Amine functional group

Ends in anamine

Nitrile

Nitrile functional group

Nitrogen containing

Ends in anenitrile

Arene/aromatic

Phenyl functional group

Ends in benzene

Halogenalkane

Halogeno functional group

Fluoro, chloro, bromo, iodo prefix

Ane suffix

When does ionic bonding occur (what electronegativity difference

If the difference in electronegativity between two elements is ≥ 1.8

Covalent bonding

The electrostatic attraction between a pair of electrons and positively charged nucleus.

Dative/co ordinate bond

• a type of covalent bond between two atoms in which the bonding electrons are supplied by one of the two atoms.

Formal charge formula

FC=no valence e - ½ bonding e - lone pair e

Polar or non polar covalent

If the difference si approximately greater than 0.5 the bond has some degree of polarity.

Can sometimes cancel out based on symmetrical shape

Differences of less than 0.4 are considered to be nonpolar.

VSEPR

See sheet practise with far right column

Van der waals

London dispersion forces

- Dipole - Dipole forces/interaction

Explain London dispersion forces

These exist due to a temporary dipole on a molecule.

Even in non-polar molecules electrons can at any one moment be unevenly distributed, this instantaneous dipole can cause or induce another dipole in a neighbouring molecule.

The result is a weak attraction - London Dispersion Force.

Increase in mass ( more electrons) = increase in London dispersion forces

All substances have them just to greater degrees

Dipole dipole interactions

These occur due to electrostatic attraction between molecules with permanent dipoles.

Strength increases with increasing polarity

Usually when NOF and the Halogens are present but for all non symetrical polar molecules

Hydrogen bonding

This occurs when hydrogen is bonded directly to a small, highly electronegative element.

e.g. N,O,F

The electronegative atom draws the covalent bonding pair of electrons away from the Hydrogen atom. The proton in the nucleus of the Hydrogen atom attracts the non-bonding electrons in N, O or F on neighbouring molecules.

A strong Dipole attraction occurs.

● σ Sigma bond what it is and when it occurs

formed when two atomic orbitals on different atoms overlap along an imaginary line drawn through the two nuclei.

(the electron distribution has axial symmetry around the axis joining two nuclei)

● occurs when

s atomic orbitals overlap with s atomic orbitals

s atomic orbitals overlap with p atomic orbitals

p atomic orbitals overlap with p atomic orbitals head on

Required for single and double and triple bonds (only once)

Pi bonds

Formed when two p orbitals overlap 'sideways' on.

○ (combination of parallel p orbitals)

● overlap occurs above and below the imaginary line drawn

through two nuclei

● One π bond is made up of two regions of electron density

In single bond once and triple bond 3x

Delocalization

In some molecules bonding electrons are less restricted to one position, we say they are delocalised. They spread out giving greater stability.

Gives bond order 1.5 of Orginal

Resonance

Resonance structures occur when there is more than one valid Lewis representations for a multiple bond in a molecule. The actual species is therefore a hybrid of the two structures - delocalisation.

The electrons in the pi bond delocalise making the molecule more stable.

Diagram to represent delocalisation.

Benzene reasons for it

1- all bond lengths and angles measured to be the same - if double bonds were shorter, it wouldnt be perfectly hexagonal so electrons must be delocalized and resonance structure

2- ring of delocalized electrons makes benzene more stable than expected

3- doesnt undergo reactions exprected for molecule with double bonds (ussually in addition reaction with bromine will absorb and lose colour, but here it remains orange)

Sp3 hybridization

Draw

Single bonds

Eg methane

Tetrahedral

Sp2 hybridization

Draw

Eg ethene

Double bonds

Trigonal planar

Sp hybridization

Triple bonds

Eg ethyne

Linear

Draw and explain bond angle, number of bonds how many electrons promoted

Allotropes of carbon sheet

Homologous series

family of compounds in which successive members differ by a common structural unit, typically CH2. Each homologous series can be described by a general formula.

CSF practise

Prefix eg meth eth

1 = Meth 2= Eth

3 = Prop 4 = But

5 = Pent 6 = Hex 7 = Hept 8 = Oct 9 = Non 10 = Dec

Saturated and unsaturated

Saturated compounds contain single bonds only and unsaturated compounds contain double or triple bonds.

Primary secondary tertiary

Cis

Solubility polar and non polar

Like dissolves like is simplified

As the non-polar section of a molecule increases, the molecule becomes less soluble in water.

Electrical conductivity polar and non polar

Covalent compounds do not contain ions therefore molecular substances aren't able to conduct electricity in the liquid or solid state.

Some polar covalent substances can ionise in certain conditions, these substances will then be able to conduct electricity.

polar

a separation of electric charge leading to a molecule or its chemical groups having an electric dipole moment, with a negatively charged end and a positively charged end.

Paper chromatography

used to separate a mixture of solutes in a solvent. The mixture to be separated is first dissolved in a solvent.

The stationary phase is the water trapped between the cellulose fibres of the paper. The mobile phase is a developing solution that travels up the stationary phase, carrying the samples with it.

chromatography retardation factor

Rf = distance travelled by solute/distance travelled by solvent.

the distance travelled by solvent is where the water line ends and the distance travelled by solute is taken from the midpoint