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Synthetic polymers

Synthetic polymers

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Question 8

This question is about the production of ethanol and its conversion into a polymer.

a.

Maltose contains the sugar C12H22O11\text{C}_{12}\text{H}_{22}\text{O}_{11}C12​H22​O11​. When yeast is added, water reacts with maltose to form glucose, C6H12O6\text{C}_6\text{H}_{12}\text{O}_6C6​H12​O6​. Write a chemical equation for this reaction.

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b.

The glucose is then converted into ethanol by the yeast:

C6H12O6(aq)→2C2H5OH(aq)+2CO2(g) \text{C}_6\text{H}_{12}\text{O}_6\text{(aq)} \rightarrow 2\text{C}_2\text{H}_5\text{OH(aq)} + 2\text{CO}_2\text{(g)} C6​H12​O6​(aq)→2C2​H5​OH(aq)+2CO2​(g)

How would you know when the reaction has stopped?

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c.

How could the solid yeast be removed from the mixture?

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d.

Ethanol can be converted into bromoethene, CH2=CHBr\text{CH}_2=\text{CHBr}CH2​=CHBr, in three stages:

  • Stage 1: Ethanol is dehydrated to form ethene, CH2=CH2\text{CH}_2=\text{CH}_2CH2​=CH2​.
  • Stage 2: Ethene is reacted to form 1,2-dibromoethane, CH2BrCH2Br\text{CH}_2\text{BrCH}_2\text{Br}CH2​BrCH2​Br.
  • Stage 3: 1,2-dibromoethane is heated to convert it into bromoethene and hydrogen bromide.

Why is the reaction in Stage 1 described as dehydration?

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e.

Identify the catalyst used in the reaction in Stage 1.

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f.

Suggest the name or formula of the substance used to react with ethene in Stage 2.

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g.

Write a chemical equation for the reaction in Stage 3.

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h.

Bromoethene can be used to make the polymer poly(bromoethene). The displayed formula for part of the poly(bromoethene) molecule is:

BrHBrHBrH∣∣∣∣∣∣−C−−C−−C−−C−−C−−C−∣∣∣∣∣∣HHHHHH \begin{array}{cccccc} \text{Br} & \text{H} & \text{Br} & \text{H} & \text{Br} & \text{H} \\ | & | & | & | & | & | \\ -\text{C}- & -\text{C}- & -\text{C}- & -\text{C}- & -\text{C}- & -\text{C}- \\ | & | & | & | & | & | \\ \text{H} & \text{H} & \text{H} & \text{H} & \text{H} & \text{H} \end{array} Br∣−C−∣H​H∣−C−∣H​Br∣−C−∣H​H∣−C−∣H​Br∣−C−∣H​H∣−C−∣H​

Draw the displayed formula for a bromoethene molecule.

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i.

Describe, in terms of structure and bonding, what happens when bromoethene molecules are converted into poly(bromoethene).

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Markscheme

Synthetic polymers Questions

  1. IGCSE
  2. /Chemistry
  3. /Synthetic polymers

10 exam-style questions on Edexcel IGCSE Chemistry Synthetic polymers. Each one has a worked solution and a mark scheme showing where the marks go.

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