Alkenes End of Chapter Test

1.  Propene, cis-pent-2-ene and trans-pent-2-ene are alkenes.

  1. Fill in the table:

Molecule / Molecular formula / Displayed formula
propene
Cis-pent-2-ene
Trans-pent-2-ene

[6]

  1. Give the general formula used to represent alkenes.______[1]
  2. Two of the molecules above are isomers. Which two? ______[1]
  3. What type of isomerism do they show? ______[1]
  4. Why is it not possible for these two isomers to interconvert at normal temperatures? ______[1]
  5. Draw and name the four alkenes with molecular formula C4H8.

[4]

  1. 3-methylpent-2-ene has two isomers. Draw them.

[2]

  1. What type of isomerism do they show? ______

[1]

2.  Give balanced symbol equations for the following reactions:

  1. Propene with bromine

______[1]

  1. Propene with hydrogen
  2. ______[1]

Name the catalyst used ______[1]

  1. Propene with hydrogen bromide ______[1]

Draw both possible products.

[2]

  1. Propene with steam ______[1]

Name the catalyst used ______[1]

Draw both possible products.

[2]

3. 

  1. What does “unsaturated” mean? ______[1]
  2. What does “hydrocarbon” mean? ______[1]
  3. Describe the bonding between the carbons in ethane. ______[2]
  4. Describe and draw the shape of an ethene molecule, labelling the bond angles.

[2]

  1. What is a “functional group”? ______[1]
  2. What functional group is present in all alkenes? ______[1]
  3. What is the chemical test for alkenes? ______[1]
  4. What would be observed if the test was positive? ______[1]

4.  Ethene reacts with bromine to give 1,2-dibromoethane.

  1. By what mechanism does bromine react with ethane? ______[1]
  2. Write a balanced equation for the reaction. ______[2]
  3. Draw the mechanism, showing curly arrows and partial charges.

[4]

  1. What is an “electrophile”?______

______[1]

  1. Which substance is the electrophile in this reaction?______[1]

5.  Ethene can be used to make poly(ethene) in an addition polymerisation reaction.

  1. Use a displayed formula to show the monomer of chloroethene.

[1]

  1. Draw the repeat unit of poly(chloroethene).

[1]

  1. Draw a section of the polymer formed from three repeat units.

[1]

  1. Give two reasons why waste polymers are difficult to dispose of.

______[2]

  1. Give two ways of dealing with waste polymers which are now replacing dumping or landfill.

______[2]

  1. Burning halogenated polymers such as PVC can release toxic waste products such as HCl into the environment. How can this be minimised? ______

______[2]

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