DP Chemistry (last assessment 2024)

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Question 22N.2.hl.TZ0.d.i

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Date November 2022 Marks available [Maximum mark: 1] Reference code 22N.2.hl.TZ0.d.i
Level hl Paper 2 Time zone TZ0
Command term Calculate Question number d.i Adapted from N/A
d.i.
[Maximum mark: 1]
22N.2.hl.TZ0.d.i

Ammonium nitrate, NH4NO3, is used as a high nitrogen fertilizer.

Cold packs contain ammonium nitrate and water separated by a membrane.

The mass of the contents of the cold pack is 25.32 g and its initial temperature is 25.2 °C. Once the contents are mixed, the temperature drops to 0.8 °C.

Calculate the energy, in J, absorbed by the dissolution of ammonium nitrate in water within the cold pack. Assume the specific heat capacity of the solution is 4.18 J g−1 K−1. Use section 1 of the data booklet.

[1]

Markscheme

«q = mcΔT = 25.32 g × 4.18 J g−1 K−1 × (25.2 °C – 0.8 °C) =» 2580 «J» ✔


Do not accept a negative value.

Examiners report

A quite simple calculation that about 80% of candidates managed to perform successfully, though a few read "drops by" rather than "drops to".

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