DP Chemistry (last assessment 2024)

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Question 19M.3.hl.TZ2.c(ii)

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Date May 2019 Marks available [Maximum mark: 2] Reference code 19M.3.hl.TZ2.c(ii)
Level hl Paper 3 Time zone TZ2
Command term Calculate Question number c(ii) Adapted from N/A
c(ii).
[Maximum mark: 2]
19M.3.hl.TZ2.c(ii)

This question is about a mug made of a lead alloy.

The rate of lead dissolving in common beverages with various pH values was analysed.

A mean daily lead intake of greater than 5.0 × 10−6 g per kg of body weight results in increased lead levels in the body.

Calculate the volume, in dm3, of tap water from experiment 8 which would exceed this daily lead intake for an 80.0 kg man.

[2]

Markscheme

«daily limit = 5.0 × 10–6 g kg–1 × 80.0 kg =» 4.0 × 10–4 «g of lead»  [✔]

«volume = 4.0 × 10 − 4  g 1.5 × 10 − 2 g d m − 3 = » 2.7 × 10–2/0.027 «dm3»  [✔]

 

Note: Award [2] for correct final answer

Examiners report

Majority of the candidates scored two marks but some struggled with the conversion of grams to milligrams.

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