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7. Ethene, C2H4, is an unsaturated hydrocarbon - Edexcel - GCSE Chemistry - Question 7 - 2019 - Paper 1
Question 7
7. Ethene, C2H4, is an unsaturated hydrocarbon. (a) Explain why ethene is an unsaturated hydrocarbon. (b) A sample of ethene is burned completely in oxygen. Write ... show full transcript
Worked Solution & Example Answer:7. Ethene, C2H4, is an unsaturated hydrocarbon - Edexcel - GCSE Chemistry - Question 7 - 2019 - Paper 1
Step 1
Explain why ethene is an unsaturated hydrocarbon.
Answer
Ethene is considered an unsaturated hydrocarbon because it contains carbon and hydrogen only, and it features a double bond between the two carbon atoms. This double bond indicates that ethene can react with additional atoms or molecules, distinguishing it from saturated hydrocarbons that only have single bonds.
Step 2
Step 3
Describe what you would see when a sample of ethene and a sample of poly(ethene) are shaken with separate, small volumes of bromine water.
Answer
When shaken with bromine water, the ethene sample would decolorize the bromine water, resulting in a loss of color, indicating a reaction due to the presence of the double bond in ethene. In contrast, the sample of poly(ethene) would not react or change the color of the bromine water, remaining either yellow/orange or demonstrating no color change, as poly(ethene) is a saturated polymer.