SPM Chemistry Form 5 Notes – Terminology and Concepts: Carbon Compounds (Part 4)

by BerryBerryTeacher

in Berry Reference (Notes)

Welcome back to Berry Berry Easy. We are pleased to present you with the Part 4 of the SPM Form 5 Chemistry notes on Carbon Compound. For those who have learnt about “alkanes” in Part 2 and “alkenes” in Part 3, now you can compare between the two groups. You’ll be exposed to the similarities and differences in the properties of the two homologous groups and also isomerism in both groups. Be sure to check out the previous three parts if you have not done so.

SPM Form 5 – Terminology and Concepts: Carbon Compounds

1. Comparing (Similarities and Differences) Properties of Alkanes and Alkenes

Physical Properties Alkanes Alkenes
Physical state Physical state changes from gas to liquid when going down the series. Same with alkanes.
Electrical conductivity. Do not conduct electricity at any state. Same with alkanes.
Boiling points and melting points Low boiling points and melting points (number of carbon atoms per molecule increases). Same with alkanes.
Density Low densities (number of carbon atom per molecule increases). Same with alkanes.
Solubility in water Insoluble in water (soluble in organic solvent) Same with alkanes.
Chemical Properties Alkanes

(Substitution reaction)

Alkenes

(Addition reaction)

Reactivity Unreactive Reactive
Combustion Burn in air and produce yellow sooty flame. Burn in air and produce yellow and sootier flame compare to alkanes.
Reaction with bromine solution No reaction. Decolourise brown bromine solution.
Reaction with acidified potassium manganate(VII) solution No reaction. Decolourise purple acidified potassium manganate(VII) solution.

2. Isomerism

Isomerism – phenomenon that two or more molecules are found to have the same molecular formula but different structural formulae.

Isomerism in alkanes

Molecular formula Number of isomers Structure name
CH4 - (no isomer) Methane
C2H6 - (no isomer) Ethane
C3H8 - (no isomer) Propane
C4H10 2 Butane2-methylpropane
C5H12 3 Pentane2-methylbutane2,2-dimethylpropane

Isomerism in alkenes

Molecular formula Number of isomers Structure name
C2H4 - (no isomer) Ethene
C3H6 - (no isomer) Propene
C4H8 3 But-1-eneBut-2-ene2-methylpropene
C5H10 5 Pent-1-enePent-2-ene2-methylbut-1-ene

3-methylbut-1-ene

2-methylbut-2-ene

As mentioned in the first part of the notes in this series, this will be a rather long set of notes. So, remember to drop by Berry Berry Easy to get updates for the notes. :)

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