DP Chemistry (last assessment 2024)

Test builder »

Question 21N.2.hl.TZ0.3c(i)

Select a Test
Date November 2021 Marks available [Maximum mark: 1] Reference code 21N.2.hl.TZ0.3c(i)
Level hl Paper 2 Time zone TZ0
Command term Calculate Question number c(i) Adapted from N/A
c(i).
[Maximum mark: 1]
21N.2.hl.TZ0.3c(i)

White phosphorus is an allotrope of phosphorus and exists as P4.

An equilibrium exists between PCl3 and PCl5.

PCl3 (g) + Cl2 (g) ⇌ PCl5 (g)

(c(i))

Calculate the standard enthalpy change (ΔH⦵) for the forward reaction in kJ mol−1.

ΔH⦵f PCl3 (g) = −306.4 kJ mol−1

ΔH⦵f PCl5 (g) = −398.9 kJ mol−1

[1]

Markscheme

«−398.9 kJ mol−1 − (−306.4 kJ mol−1) =» −92.5 «kJ mol−1» ✔

Syllabus sections