Complete the sentence by putting a cross (X) in the box next to your answer - Edexcel - GCSE Chemistry - Question 4 - 2016 - Paper 1
Question 4
Complete the sentence by putting a cross (X) in the box next to your answer.
Alkenes are
A saturated carbohydrates
B saturated hydrocarbons
C unsaturated carb... show full transcript
Worked Solution & Example Answer:Complete the sentence by putting a cross (X) in the box next to your answer - Edexcel - GCSE Chemistry - Question 4 - 2016 - Paper 1
Step 1
Complete the sentence:
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Answer
Alkenes are D unsaturated hydrocarbons. Alkenes contain at least one carbon-carbon double bond, making them unsaturated.
Step 2
(b)(i) Draw the structure of a propene molecule:
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Answer
The structure of propene (C₃H₆) can be illustrated as follows:
H H H
| | |
H - C = C - C - H
| |
H H
In this structure, the double bond between the first two carbon atoms is clearly shown, and all hydrogen atoms are represented.
Step 3
(b)(ii) Describe a test to differentiate propane and propene:
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Answer
To distinguish between the two gases:
Add bromine water (solution) to a sample of the gas.
For propene:
The bromine water will turn from brown/orange to colourless due to the addition reaction with the double bond in propene.
For propane:
The bromine water will remain brown/orange, indicating no reaction occurs.
This test effectively demonstrates the unsaturation present in propene as opposed to the saturation in propane.
