DP Chemistry (last assessment 2024)

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Question 18N.3.hl.TZ0.3d.i

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Date November 2018 Marks available [Maximum mark: 1] Reference code 18N.3.hl.TZ0.3d.i
Level hl Paper 3 Time zone TZ0
Command term State Question number d.i Adapted from N/A
d.i.
[Maximum mark: 1]
18N.3.hl.TZ0.3d.i

The presence of very small amounts of lead in calcium-based antacids can be determined using inductively coupled plasma-mass spectroscopy (ICP-MS).

Chelating agents can be used to treat heavy metal poisoning.

(d.i)

State one feature of a chelating agent.

[1]

Markscheme

Any one of:

two «or more» lone/non-bonding pairs on different atoms

OR

two «or more» atoms/centres that act as Lewis bases ✔

 

form «at least» two coordination/coordinate bonds

OR

«at least» two atoms can form coordination/coordinate bonds ✔

 

Reference to “on DIFFERENT atoms” required.

Accept “dative «covalent» bond” for “coordination/coordinate bond”.

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