Compare alkane and alkene

Comparing chemical properties

Combustion
Procedure:
1. Pour 2 cm3 of propane and propene into each

crucible.
2. The liquids are lighted.
3. When burning occurs, filter paper is placed

on top of the flame.
4. All the observation is recorded.

Observation:
Propane:
Burn in air, producing yellow sooty flame
Propene:
Burn in air, producing yellow and a very sooty flame

Conclusion:
Propene is more reactive than propane

Describe two chemical test to differentiate
between hexane and hexene

• Reaction with bromine water

Procedure:
1. Pour about [2-5 ] of hexane into a test tube.
2. Add 4-5 drops of bromine water and shake it.
3. Observe any changes and repeat with hexene.

Observation:
Hexane: Brown colour of bromine remains unchanged
Hexene: Brown colour of bromine decolourise/turn

colourless

• Reaction with acidified potassium manganate(VII) solution

Procedure:
1. Pour about [2-5 ] of hexane into a test tube.
2. Add 4-5 drops of acidified potassium manganate(VII)

solution and shake it.
3. Observe any changes and repeat with hexene.

Observation:
Hexane: Purple colour of KMnO4 remains unchanged
Hexene: Purple colour of KMnO4 decolourise/turn colourless

Determine which one is more soot between
hexane and hexene when burn in oxygen. Give
your reason.

Hexane, C6H14 Hexene, C6H12
= 6(12) x 100 = 6(12) x 100

[6(12)+14(1)] [6(12)+12(1)]
= 83.72% = 85.71%

Hexene has high percentage of carbon by mass than
hexane.

So, hexene burn with more sooty flame