Free States of matter questions for AS Level Chemistry (9701), part of Physical chemistry. Each question has the answer and the marking points an examiner would look for.
Generate a full States of Matter worksheet →All Physical chemistry questionsReal gases deviate from ideal gas behaviour.
1 Intermolecular forces cause the real volume to be lower than predicted.
2 Ideal gas molecules have significant volume.
3 Real gases behave most ideally at low temperature.
Which statements are correct?
Answer: C
Under which conditions does a gas behave most like an ideal gas?
Answer: C
Which term is described by this statement?
“A gas whose molecules have zero volume and no intermolecular forces.”
Answer: B
Real gases deviate from ideal gas behaviour.
1 Deviations are greatest at high pressure and low temperature.
2 Real gases behave most ideally at low temperature.
3 Intermolecular forces cause the real volume to be lower than predicted.
Which statements are correct?
Answer: B
This question is about the structures of solids and the behaviour of real gases.
Substance A melts at 1610 °C and does not conduct when molten. Substance B melts at 801 °C and conducts only when molten. Substance C melts at 114 °C and does not conduct. Deduce the structure of each.
Explain why ice is less dense than liquid water.
State and explain the conditions under which a real gas deviates most from ideal behaviour.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | A giant covalent; B giant ionic; C simple molecular A giant covalent B1 B giant ionic B1 C simple molecular B1 | 3 |
| (b) | open lattice from hydrogen bonds each molecule forms hydrogen bonds in a regular open lattice M1 molecules are further apart than in the liquid M1 | 2 |
| (c) | high pressure, low temperature high pressure: molecular volume is significant M1 low temperature: intermolecular forces are significant M1 | 2 |
A volatile liquid of mass 0.250 g is vaporised. The vapour occupies 80 cm³ at 300 K and 101 kPa.
Calculate the relative molecular mass of the liquid.
State two assumptions of the ideal gas equation.
Explain why real gases deviate from ideal behaviour at high pressure.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | 77.1 pV = nRT with correct units C1 n = 3.24 × 10−3 mol C1 Mr = 77.1 A1 | 3 |
| (b) | negligible volume; no intermolecular forces molecules have negligible volume B1 no intermolecular forces (elastic collisions) B1 | 2 |
| (c) | molecules close; volume and forces significant molecules are close together B1 their volume and the intermolecular forces become significant B1 | 2 |
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Meet Riyaz →Original Cambridge-style practice questions written for mentorriyaz.in. These are not Cambridge past paper questions, and this site is not affiliated with or endorsed by Cambridge University Press & Assessment. Updated 2026-11-04. Paper generator · mentorriyaz.in