C15: States of Matter, Kinetic Particle Theory and Diffusion
Official Cambridge & Imperial ESAT specification requirements for States of Matter, Kinetic Particle Theory and Diffusion on the Chemistry paper. Understand the syllabus boundaries, spot distractor traps engineered by examiners, and master the 2-step Sub-90 shortcuts that compress solve time well below the 88.8-second cutoff.
Official Syllabus Subtopics
Requirements specified in the UAT-UK framework
- 1Solid, liquid, and gas states in terms of particle arrangement, motion, and intermolecular forces
- 2Phase transitions: melting, freezing, boiling, condensing, subliming
- 3Heating and cooling curves: constant temperature plateaus during latent heat absorption/release
- 4Gas diffusion and Graham’s law relationship: diffusion velocity v ∝ 1 / √Mᵣ
Sub-90 Exam Speed Tips
How top candidates solve this spec under the 88.8s clock
Gases with lower molar mass Mᵣ diffuse faster (e.g. NH₃ at Mᵣ = 17 travels faster than HCl at Mᵣ = 36.5).
During phase change plateaus, kinetic energy is constant while potential energy increases as bonds break.
Examiners engineer distractor options using common algebraic expansions and sign slips. Always test structural ratios or invariants before calculating arithmetic values.
Tested Topics in Specification C15
Master the individual question patterns and Sub-90 shortcuts for this specification.
Kinetic Particle Theory, Heating/Cooling Phase Curves, Fractional Distillation & Gas Diffusion
For state-at-T tables, write T(target) directly between the MP and BP columns: Liquid strictly requires MP < T(target) < BP (watch negative signs: -70 is between -100 and -40!). In diffusion tubes, lighter gas (smaller Mᵣ) travels further.
Ready to Master Specification C15 Under Exam Conditions?
Practice timed questions under the authentic Pearson VUE interface with live split stopwatch pacing, dry-wipe scratchpad, and distractor forensics.