Page 21 - Ranger SPM 2022 Chemistry

Chemistry SPM Chapter 2 Carbon Compound
• Exist as colourless liquid at room • Exist as colourless liquid at room
temperature temperature with a sharp smell
• Have a sharp smell and highly and sour taste
volatile • Have pH value lower than 7
• Have low boiling point • Corrosive
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• Smaller alcohol molecules like • Low boiling point
methanol, ethanol and propanol • Methanoic acid, ethanoic acid
are miscible with water. and propanoic acid are soluble in
• However, solubility in water water.
decreases when the molecular size • However, solubility in water
increases. decreases when the molecular size
• When the number of carbon atoms increases.
per molecule increases, • When the number of carbon atoms
(a) Boiling point increases because per molecule increases,
- molecular size increases. (a) Boiling point increases because
– van der Waals attraction - molecular size increases.
force between molecules - van der Waals attraction
becomes stronger. force between molecules
- more heat energy is needed becomes stronger.
to overcome the van der - more heat energy is needed
Waals attraction force. to overcome the van der
(b) Viscosity of molecules Waals attraction force.
increases. (b) Density of molecules increases.
(c) Density of molecules increases. • Carboxylic acid can conduct
(d) Molecules become less electricity in aqueous solution due
flammable. to the presence of free moving
9. Physical properties of carboxylic ions.
acids SPM TIP
• Carboxylic acids are non-
hydrocarbon organic compounds • Alkanes, alkenes and alkynes
containing carbon, hydrogen and are not soluble in water. All three
oxygen atoms. hydrocarbons are highly flammable.
• Carboxylic acids have the same
chemical properties as strong acids.

2.3 Chemical Properties and Interconversion of
Compounds between Homologous Series
Form 5

Alkane

Nickel, Hydrogenation
180 °C
Hydration Oxidation
Alkene Alcohol Carboxylic acid
60 atm, 300 °C, Acidified KMnO (aq)/
4
H PO (aq) Acidified K Cr O (aq)
3 4 2 2 7
Platinum Hydrogenation Concentrated Esterification
H SO (aq)
4
2
Alkyne Ester
150

02.5 RANGER SPM CHEMISTRY 2P.indd 150 29/03/2022 2:28 PM