Chemistry equations and general

n =

m / Mr

c x V

V / 24 (gas)

number of particles / 6.02 × 10²³

^pV=nRT

TOF mass spectrometry

t =

Answer should lie around: x10^-5/-6/-7

ThErmal cracking

High pressure - expensive and dangerous

High temperature - expensive

Produces:

• Short chain alkanes

• AlkEnes

  Which can be used for feedstock and sold.

Catalytic Cracking

Slight pressure

High temperature

Zeolite catalyst

Products:

• aromatic hydrocarbon

• branched alkAnes

• cycloalkanes

Examples of electrophiles

Dipole

Halogen: Br-Br

Hydrogen halide: H-Br

Sulfuric Acid: H₂SO₄

Electrophilic Addition to an unsymmetrical alkEne

Electrophilic Addition to a symmetrical alkEne

Examples of Nucleophiles

Lone Pairs

Ammonia: NH₃

Potassium/Sodium hydroxide: OH^- (aq)

Cyanide ion: CN^-

Markovnikov's rule

When a hydrogen halide reacts with an asymmetric alkene, the hydrogen atom of the the hydrogen halide is more likely to bond to the carbon atom which is attached to the greater number of hydrogen atoms.

Phosphoric acid

H₃PO₄

Hydration of alkenes conditions

300^oC

60 atm

phosphoric acid catalyst

Hydration of alkenes mechanism

5 curly arrows

Carbocation intermediate

O⁺ with 1 lp, in second intermediate

Regenerated H₃PO₄

Sulfuric Acid

H₂SO₄

Plasticiser

A small molecule that fits between polymer chains, causing them to move further apart. This weakens IMF between chains so they can now move over one another, resulting in a more flexible polymer.

IUPAC name for this molecule

Ethane - 1,2 - diol

IUPAC name for this molecule

Propane - 1,2,3 - triol

IUPAC name for this molecule

2-chloropropan-1-ol

IUPAC name for this molecule

3-hydroxypropanal

(aldehyde group takes priority over alcohol group, alcohol is represented by ‘hydroxy’)

IUPAC name for this molecule

1-hydroxypropan-2-one

(ketone group takes priority over alcohol group, alcohol is represented by ‘hydroxy’)

Oxidation and reflux of alcohols

	Oxidation	Reflux
Primary	Aldehyde	Carboxylic acid
Secondary	Ketone	/
Tertiary	/	/

Name an oxidising agent used for alcohols

Colour change

Acidified potassium dichromate and warmed.

K₂Cr₂O₇ + H₂SO_4(aq)

Orange dichromate ions (Cr₂O_7^2-) are reduced to green Cr³⁺ ions.

SO must be primary or secondary alcohol.

Aldehyde can be distilled off as it has a lower bp than alcohol or can be refluxed with excess K₂Cr₂O₇ to form a carboxylic acid.

Elimination reaction of alcohols

Alcohol → alkEne + water

H₂SO_4(l) Catalyst H⁺

2 lp on O

Nucleophilic substitution OH^-

Conditions

Halogenoalkane must be dissolved in ethanol to make it able to react with aqueous OH^-.

Heat under reflux to increase rate.

Acid

Proton donor

Base

Proton acceptor (H⁺)

When investigating rate of nucleophilic substitution of different halogenoalkanes, we use nucleophile…

H₂O, not OH^- as they would react with AgNO₃ to form insoluble silver hydroxide.

Rate of nucleophilic substitution of different halogenoalkanes

Iodoalkanes > Bromoalkanes > Chloroalkanes

Chloroalkanes have the highest bond enthalpy.

Nucleophilic substitution NH₃

1lp on N in aminoalkane

Nucleophilic Substitution CN^-

Very useful reaction as it allows an increase in length of carbon chain!

Elimination of a halogenoalkane

KOH _(ethanolic)

NaOH _(ethanolic)

Reflux

In absences of water it acts as a base.

Ozone & UV light equation

Amount stays constant due to reverisble reaction

(Initiation) photodissociation equation

Chlorofluorocarbon + ozone propagation steps

Infrared Spectroscopy

Bonds vibrate at different rates, which is slower between heavier atoms.

Bonds absorb radiation at the same frequency as they vibrate - which lies within the infrared region of electromagnetic spectrum for organic molecules.

An absorption spectrum is produced.

Fingerprint region is complex (<1500).

TMS name and structure

Tetra Methyl Silicane

How many H environments does TMS have?

1

Why is TMS a good reference?

1. Only a small amount needed as there are 12H in the same environment - so gives a strong signal.

2. Singlet pattern as only one H environment.

3. Contains silicon so chemical shift different to any organic compound so we can compare.

4. It is inert so doesn’t react with what we are analysing.

5. Non-toxic.

6. Volatile so can easily distil off and reuse.

7. Can use for both 1H and 13C n.m.r.