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Propene is an alkene - Edexcel - GCSE Chemistry - Question 6 - 2012 - Paper 1
Question 6
Propene is an alkene. The formula of its molecule is C₃H₆. a) (i) Draw the structure of a propene molecule, showing all of the bonds. (ii) One molecule of decane,... show full transcript
Worked Solution & Example Answer:Propene is an alkene - Edexcel - GCSE Chemistry - Question 6 - 2012 - Paper 1
Step 1
Draw the structure of a propene molecule, showing all of the bonds.
Answer
The structure of a propene molecule (C₃H₆) is represented as follows:
H H
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H - C = C - C - H
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H H
In this diagram:
- Each line represents a bond between carbon (C) and hydrogen (H) atoms.
- The double bond between the first two carbon atoms signifies that propene is an alkene.
Step 2
Step 3
Describe a test to show which gas is propane and which gas is propene.
Answer
To distinguish between propane and propene, the following test can be performed:
- Test for Unsaturation: Use bromine water as an indicator.
- Procedure: Add a few drops of bromine water to a test tube containing a sample of the gas.
- Observation:
- If the reddish-brown color of bromine water disappears, it indicates the presence of an alkene (propene) due to its unsaturation (double bond).
- If the color remains, the gas is propane (which is a saturated hydrocarbon and does not react with bromine water).
This test effectively identifies propene as the unsaturated hydrocarbon among the two gases.