Question 1Multiple choice · 1 markA* challenge
A gas syringe of gas is heated at constant pressure.
What happens to the gas?
- A Its particles get larger.
- B Its mass increases.
- C Its volume decreases.
- D Its volume increases.
Show answer
Answer: D
Free Solids, liquids & gases questions for IGCSE Chemistry (0620), part of States of matter. Each question has the answer and the marking points an examiner would look for.
Generate a full Solids, Liquids & Gases worksheet →All States of matter questionsA gas syringe of gas is heated at constant pressure.
What happens to the gas?
Answer: D
Which change of state needs energy to be taken in?
Answer: A
Which statement describes sublimation?
Answer: D
A sample of a substance is cooled from 120 °C to 20 °C. Its melting point is 80 °C and its boiling point is 110 °C.
State the physical state of the substance at 120 °C, at 95 °C and at 20 °C.
Explain why the temperature stays constant while the substance freezes.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | gas, liquid, solid 120 °C gas B1 95 °C liquid B1 20 °C solid B1 | 3 |
| (b) | energy released as forces form energy is released as attractive forces form between particles B1 this balances the energy lost to the surroundings B1 | 2 |
Ice cubes melt in a glass of water on a warm day.
Describe what happens to the particles of ice as it melts.
State the term for a solid changing directly into a gas.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | vibrate more, break from fixed positions particles gain energy and vibrate more B1 they break free from their fixed positions and can move past each other B1 | 2 |
| (b) | sublimation sublimation B1 | 1 |
A student heats a sample of salol until it melts, then lets it cool, recording its temperature every minute. Fig. 6.1 shows the cooling curve.
Use Fig. 6.1 to find the melting point of the substance.
State what is happening to the substance between 2 and 6 minutes.
Explain why the temperature stays constant between 2 and 6 minutes.
Describe the changes in the arrangement and motion of the particles as the liquid freezes.
Explain why a gas can be compressed easily but a liquid cannot.
Suggest why the student uses a water bath rather than a Bunsen burner to heat the substance.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | 43 °C 43 °C B1 | 1 |
| (b) | freezing / solidifying it is freezing (changing from liquid to solid) B1 | 1 |
| (c) | energy released as bonds/forces form between particles; balances energy lost to surroundings attractive forces form between the particles as the solid forms B1 energy is released B1 this balances the energy lost to the surroundings, so the temperature does not fall B1 | 3 |
| (d) | liquid: random, moving past each other; solid: regular lattice, vibrate in fixed positions; particles slow down in the liquid the particles are randomly arranged and slide past each other B1 in the solid they are in a regular arrangement B1 they only vibrate about fixed positions (less kinetic energy) B1 | 3 |
| (e) | gas particles far apart; liquid particles touching gas particles are far apart with large spaces between them B1 liquid particles are close together / touching B1 | 2 |
| (f) | even, controlled heating; substance is flammable / below 100 °C gives gentle, even heating B1 the substance is flammable / melts below 100 °C B1 | 2 |
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