DP Chemistry (last assessment 2024)

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Question 17N.3.sl.TZ0.9c

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Date November 2017 Marks available [Maximum mark: 2] Reference code 17N.3.sl.TZ0.9c
Level sl Paper 3 Time zone TZ0
Command term Explain Question number c Adapted from N/A
c.
[Maximum mark: 2]
17N.3.sl.TZ0.9c

Lactose is a disaccharide formed by the condensation reaction of the monosaccharides galactose and glucose.

(c)

Explain how the inclusion of carbohydrates in plastics makes them biodegradable.

[2]

Markscheme

Any two of:

makes the plastic more hydrophilic/water soluble

carbohydrates are broken down/hydrolysed by bacteria/microorganisms

makes plastic more accessible to bacteria as holes/channels are created

OR

plastic of lower density is more permeable/susceptible to water/oxygen/heat/pressure

weakens intermolecular/London/dispersion/instantaneous induced dipole-induced dipole forces «between polymer chains in the plastic»

Accept “van der Waals/vdW” for “London” forces.

[Max 2 Marks]