Biodegradability and disposal of polymersAQA A-Level Chemistry: Subtopic test

1. 1
   A council is choosing between poly(propene) crates and polyester food trays for a school canteen. It wants to know how each material will behave if it ends up in the environment.

   (a)

   Which statement about poly(propene) is correct?

   [1 mark]

   • AIt is biodegradable because it contains C–H bonds
   • BIt is chemically inert and not biodegradable
   • CIt is broken down by hot aqueous acid to propene
   • DIt is a condensation polymer

   (b)

   Which bond is broken when a polyester is hydrolysed?

   [1 mark]

   • AThe C–C bond in the polymer chain
   • BThe C=O bond
   • CThe C–H bond
   • DThe C–O bond in the ester link

   (c)

   Explain why poly(propene) is chemically inert.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   Fishing nets made from nylon-6,6, a polyamide, are sometimes lost at sea. Nylon-6,6 is made from hexanedioic acid and 1,6-diaminohexane.

   (a)

   Which pair of organic compounds forms when the amide links in nylon-6,6 are completely hydrolysed, ignoring any reaction with acid or alkali?

   [1 mark]

   • AHexanedioic acid and 1,6-diaminohexane
   • BHexanedioic acid and hexane-1,6-diol
   • CHexanedioic acid and 1,6-dichlorohexane
   • DTwo molecules of 6-aminohexanoic acid

   (b)

   Which statement is an advantage of burning waste polyamide in an energy-from-waste plant?

   [1 mark]

   • AIt produces no carbon dioxide
   • BIt burns without producing any gases
   • CThe heat released can be used to generate electricity
   • DIt allows the monomers to be recovered unchanged

   (c)

   The nylon-6,6 is hydrolysed by hot aqueous acid. Give the formulae of the two organic products.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A local authority collects poly(ethene) packaging waste. It can send the waste to landfill, burn it in an energy-from-waste plant, or recycle it.

   (a)

   State one advantage and two disadvantages of disposing of poly(ethene) waste in landfill.

   [3 marks]

   (b)

   The authority burns 1.00 tonne (1.00 × 10⁶ g) of poly(ethene) completely in air. Calculate the mass of carbon dioxide produced in grams. Use Ar: H = 1.0, C = 12.0, O = 16.0.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A drinks company makes bottles from poly(ethylene terephthalate), PET, a polyester made from benzene-1,4-dicarboxylic acid and ethane-1,2-diol. It makes carrier bags from poly(ethene). Waste from both is collected for disposal by landfill, incineration or recycling.

   (a)

   Evaluate the use of landfill, incineration and recycling for disposing of the company's waste polymers.

   [6 marks]

   (b)

   Explain why PET can be hydrolysed and is biodegradable but poly(ethene) cannot be hydrolysed and is not. Name the products of the hydrolysis of PET.

   [6 marks]

   Total for question 4: 12 marks

End of questions