CIE A Level Chemistry: Alkenes: Production, Reactions, and Markovnikov's Rule

Alkenes

Hydrocarbons with at least one C=C double bond.

Elimination Reaction

Reaction where a small molecule is lost.

Halogenoalkane

Alkane with a halogen substituent.

Ethanolic Sodium Hydroxide

Sodium hydroxide dissolved in ethanol.

Dehydration Reaction

Elimination of water from alcohols.

Aluminium Oxide

Catalyst used in dehydration reactions.

Cracking

Breaking down long hydrocarbons into smaller ones.

Electrophilic Addition

Electrophile adds to a double bond.

Hydrogenation

Addition of hydrogen across a double bond.

KMnO4

Potassium manganate(VII), a strong oxidizing agent.

Diol

Organic compound with two hydroxyl groups.

Addition Polymerisation

Monomers join to form long-chain polymers.

Monomer

Small reactive molecule forming polymers.

Hydrogen Halide

Compound formed from hydrogen and halogen.

Oxidation

Reaction involving loss of electrons or hydrogen.

Propanone

A ketone produced from oxidation of alkenes.

Carbon Dioxide

Gas produced from combustion and oxidation.

Water

Product of dehydration and oxidation reactions.

Feedstock

Raw material used in chemical processes.

Hydrocarbon

Organic compound consisting solely of hydrogen and carbon.

Pumice

Volcanic rock used as a catalyst.

Reaction Conditions

Specific parameters affecting chemical reactions.

Electrophile

Species that accepts electron pairs.

Nucleophilic Substitution

Replacement of one nucleophile by another.

Hydrocarbon Combustion

Reaction with oxygen producing CO2 and H2O.

Double Bond Position

Location of C=C in larger alkenes.

Small Alkenes

Gaseous alkenes like ethene, propene at room temperature.

Catalyst

Substance that speeds up a reaction without being consumed.

Polymer backbone

Carbon chain with monomers containing side chains.

Propene

Monomer with a carbon chain and methyl groups.

Poly(chloroethene)

Versatile plastic also known as PVC.

Unsaturation test

Detects double bonds using bromine water.

Bromine water

Orange/yellow solution used for unsaturation testing.

Decolourisation

Color change indicating unsaturation in compounds.

Electrophilic addition

Addition of electrophiles to double bonds.

Hydrogen bromide (HBr)

Polar molecule used in electrophilic addition.

Carbocation

Positively charged carbon with three bonds.

Primary carbocation

Carbocation with one alkyl group attached.

Secondary carbocation

Carbocation with two alkyl groups attached.

Tertiary carbocation

Carbocation with three alkyl groups attached.

Inductive effect

Electron donation from alkyl groups stabilizing carbocations.

Markovnikov's Rule

Predicts halogen attachment to most substituted carbon.

Electrophilic addition mechanism

Process showing how electrophiles react with alkenes.

Major product

Product from the most stable carbocation.

Minor product

Product from the least stable carbocation.

Nucleophile

Species that donates electrons in reactions.

Heterolytic bond cleavage

Unequal breaking of a bond forming ions.

Addition reaction

Reaction where two molecules combine to form one.

Bromide ion (Br-)

Negatively charged bromine ion formed in reactions.

Electronegativity

Ability of an atom to attract electrons.

Polar molecule

Molecule with partial positive and negative charges.

Non-polar molecule

Molecule with equal sharing of electrons.

Electrophilic attack

Electrophile approaches electron-rich double bond.

Carbocation stability

Stability order: tertiary > secondary > primary.

Addition of Br2

Bromine reacts with alkenes forming dibromo products.

Reaction mechanism

Step-by-step sequence of a chemical reaction.