Sketch four repeating units of the polymer to show atactic and isotactic polypropene.

State the chemical reason why plastics do not degrade easily.

Compare two ways in which recycling differs from reusing plastics.

Civilizations are often characterized by the materials they use.

Suggest an advantage polymers have over materials from the iron age.

Do not accept syndiotactic (alternating orientation of the CH₃ groups), eg,

for M1 or M2.

Accept any correct atactic ordering of CH₃ groups.

Penalize missing hydrogens or incorrect bond connectivities once only.

Accept skeletal structures.

Ignore continuation bonds, brackets and “n” indices in structures.

[2 marks]

strong covalent bonds

Accept “moisture cannot get inside the plastic matrix, and bacteria cannot live without moisture, so they cannot attack the polymer chains”.

Accept “bacteria lack the enzymes required to break down the hydrocarbon chains”.

[1 mark]

Any two of:

Recycling: shredded/melted/reformed AND Reuse: used in its current form

recycling is more energy intensive «than reusing»

recycling degrades the quality of plastic but reusing «typically» does not

recycling breaks down original product to form a new product whereas reuse extends product life

[2 marks]

more pliable/flexible materials

OR

more durable/non-corrosive/longer-lasting materials

OR

greater variety of materials

OR

lower density

OR

can be clear/translucent

Accept “more adaptable”.

Do not accept just “more useful”.

[1 mark]