| Date | May 2017 | Marks available | 1 | Reference code | 17M.3.hl.TZ2.3 |
| Level | HL | Paper | 3 | Time zone | TZ2 |
| Command term | Estimate | Question number | 3 | Adapted from | N/A |
Question
Polymer nanocomposites often have better structural performance than conventional materials. Lithographic etching and metal coordination are two methods of assembling these nanocomposites.
Dendrimers are highly branched nanoparticles with a wide range of usage. One such dendrimer is PAMAM, or polyamidoamine.
The first step in the synthesis is to make the core by reacting ethane-1,2-diamine with methylpropenoate.
Estimate the atom economy of this first step.
Suggest, giving one reason, whether this is an addition or condensation reaction.
Subsequent steps proceed under differing conditions, forming the dendrimer polymer with the following repeating unit.
State the name of one functional group in this repeating unit.
Markscheme
100%
Accept “almost 100%” if a catalyst is referred to.
[1 mark]
addition AND no atoms removed/all atoms accounted for/no loss of water/ammonia/inorganic by-product/small molecules
OR
addition AND there is only one «reaction» product
[1 mark]
amido
OR
amino
Accept “amide/carboxamide/carbamoyl” for “amido”.
Accept “amine“ for “amino”.
Accept “carbonyl”.
[1 mark]
