Difficulty guide
The label describes the problem, not your ability.
1/5 - Foundational
Warm-up setup; checks one basic idea.
2/5 - Routine exam skill
Normal syllabus skill; usually one main rule or interpretation.
3/5 - Standard multi-step
Exam-style problem with multiple steps or a common trap.
4/5 - Hard exam skill
High-end exam problem; combines methods carefully.
5/5 - Challenge
Stretch problem beyond normal exam pressure.
Question
(a) What physical process occurs during the lower horizontal part? (1 mark)
(b) Why does temperature remain constant during a horizontal part even though heat is supplied? (1 mark)
(c) If of the substance absorbs during one plateau, find the latent heat for that change. (1 mark)
(d) Which part of the curve would be used to calculate specific heat capacity of a single phase? (1 mark)