| Date | November 2016 | Marks available | 2 | Reference code | 16N.3.hl.TZ0.10 |
| Level | HL | Paper | 3 | Time zone | TZ0 |
| Command term | Compare and contrast | Question number | 10 | Adapted from | N/A |
Question
The Fenton and Haber–Weiss reactions convert organic matter in waste water to carbon dioxide and water.
Compare and contrast the Fenton and Haber–Weiss reaction mechanisms.
Adsorption and chelation are two methods of removing heavy metal ion pollution from the environment.
(i) Describe the process of adsorption.
(ii) Deduce the structure of the complex ion formed by the reaction of three H2N−CH2−CH2−NH2 chelating molecules with a mercury(II) ion.
Markscheme
One similarity:
both involve hydroxyl/•OH «radicals»
One difference:
Accept “hydroxy” for “hydroxyl”.
Do not penalize missing radical symbols if consistent throughout.
Accept “H2O2 → 2•OH” for the Fenton mechanism.
i
molecules/ions/substances are attracted to/form «non-covalent» interactions with the surface of the adsorbent
ii
Do not penalize missing charge or square brackets.
Bonds to Hg must be shown (in any format).
