DP Chemistry (first assessment 2025)
Question 19M.2.HL.TZ1.b
| Date | May 2019 | Marks available | [Maximum mark: 1] | Reference code | 19M.2.HL.TZ1.b |
| Level | HL | Paper | 2 | Time zone | TZ1 |
| Command term | Formulate | Question number | b | Adapted from | N/A |
b.
[Maximum mark: 1]
19M.2.HL.TZ1.b
Formulate the equation for the complete hydrolysis of a starch molecule, (C6H10O5)n.
[1]
Markscheme
(C6H10O5)n (s) + nH2O (l) → nC6H12O6 (aq) [✔]
Note: Accept “(n-1)H2O”.
Do not award mark if “n” not included.
Examiners report
Also proved challenging, with many candidates unable to write an equation for the hydrolysis of a starch molecule (C6H10O5)n. The n was often omitted from otherwise correct equations or the product was incorrectly given as (C6H12O6)n.
Syllabus sections
Structure 2. Models of bonding and structure » Structure 2.4—From models to materials » Structure 2.4.6—Condensation polymers form by the reaction between functional groups in each monomer with the release of a small molecule. Represent the repeating unit of polyamides and polyesters from given monomer structures.