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Question 19M.3.hl.TZ1.8b

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Date May 2019 Marks available [Maximum mark: 1] Reference code 19M.3.hl.TZ1.8b
Level hl Paper 3 Time zone TZ1
Command term Formulate Question number b Adapted from N/A
b.
[Maximum mark: 1]
19M.3.hl.TZ1.8b

Starch is a natural polymer of glucose.

(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.