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Figure 16 shows the structure of a molecule of dichloroethene - Edexcel - GCSE Chemistry - Question 10 - 2020 - Paper 1
Question 10
Figure 16 shows the structure of a molecule of dichloroethene. Cl | H – C = C – H ... show full transcript
Worked Solution & Example Answer:Figure 16 shows the structure of a molecule of dichloroethene - Edexcel - GCSE Chemistry - Question 10 - 2020 - Paper 1
Step 1
Describe how dichloroethene monomers form a polymer.
Answer
Dichloroethene monomers form a polymer through a process called polymerization. This typically involves the breaking of the double bond between the carbon atoms in the dichloroethene monomer. As the double bond breaks, the monomers link together to form long chains, resulting in a polymer known as polydichloroethene. This process can occur via addition polymerization, where multiple monomer units combine without the loss of any small molecules.
Step 2
Step 3
Separate samples of dichloroethene and polydichloroethene are shaken with a few drops of bromine water. What would be seen?
Answer
B only the dichloroethene and bromine water goes colourless. This is due to the presence of the double bond in dichloroethene which reacts with bromine, while polydichloroethene does not.
Step 4
Step 5
Explain one property that a plastic food wrapping must have.
Answer
One property that a plastic food wrapping must have is that it should be impermeable to air and moisture. This property helps in keeping the food fresh by preventing the exchange of oxygen and water vapor, which can lead to spoilage.
Step 6
Calculate the mass of dichloroethene that has not reacted.
Answer
To find the mass of dichloroethene that has not reacted:
Total mass = 500 tonnes
Reaction percentage = 96.5%
Unreacted percentage = 100% - 96.5% = 3.5%
Mass not reacted = 500 tonnes × 0.035 = 17.5 tonnes.
Therefore, the mass of dichloroethene that has not reacted is 18 tonnes (to two significant figures).