GCSE Combined Science Particle model and density questions by topic

This question is about the three states of matter.

1. (a)Describe the arrangement of particles in a solid.[1]
2. (b)Name the change of state from liquid to solid.[1]
3. (c)State which state of matter is easily compressed.[1]
4. (d)State what is meant by internal energy.[1]

This question is about density.

1. (a)Write the equation linking density, mass and volume.[1]
2. (b)State two units in which density can be given.[1]
3. (c)Convert a density of 1 g/cm³ into kg/m³.[1]
4. (d)Which has the greater density: 1 kg of iron or 1 kg of feathers? Explain.[1]

A block has mass 720 g and volume 240 cm³.

1. (a)Write the equation used to calculate density.[1]
2. (b)Calculate the density of the block in g/cm³.[2]
3. (c)State what happens to the density if a larger block of the same material is used.[1]

This question is about finding the density of a liquid.

1. (a)Name the instrument used to measure the liquid's volume.[1]
2. (b)Describe how the liquid's mass is found.[1]
3. (c)An empty measuring cylinder weighs 80 g; with 100 cm³ of liquid it weighs 176 g. Calculate the density of the liquid.[2]

A substance is heated steadily from solid to gas and its temperature is plotted against time.

1. (a)State what a flat (horizontal) section of the graph represents.[2]
2. (b)Explain why the temperature stays constant during that section.[2]
3. (c)Name the change of state taking place when the flat section occurs just above the liquid's warming stage.[1]

An irregular metal object has mass 356 g. Lowered into a displacement can, it pushes out 40 cm³ of water.

1. (a)State the volume of the object.[1]
2. (b)Calculate the density of the metal in g/cm³.[2]
3. (c)Copper's density is 8.9 g/cm³. Suggest what the object is made of.[1]
4. (d)State one precaution that improves the accuracy of the displaced-volume measurement.[1]

This question is about the energy involved in boiling water.

1. (a)Explain why energy must still be supplied to water boiling at 100 °C.[2]
2. (b)One kilogram of water is melted, then boiled away. State which change of state needs more energy and why.[2]
3. (c)Write the equation linking energy, mass and specific latent heat.[1]

This question is about gas pressure.

1. (a)Explain, in terms of particles, how a gas exerts pressure on its container.[2]
2. (b)A sealed, rigid can of gas is warmed in the sun. Explain why the pressure inside rises.[2]
3. (c)State one safety precaution that follows from (b).[1]

A 2.0 kW kettle is left switched on while boiling. Ice has a specific latent heat of fusion of 334 000 J/kg.

1. (a)Calculate the energy needed to melt 0.25 kg of ice.[2]
2. (b)Calculate how long the kettle would take to supply that energy, assuming all its power heats the ice.[2]
3. (c)State one assumption made in (b).[1]

A fixed mass of gas occupies 4.0 m³ at a pressure of 200 kPa. It is compressed slowly to 1.6 m³ at constant temperature.

1. (a)Calculate the value of pV before compression.[1]
2. (b)Calculate the new pressure.[2]
3. (c)Explain the pressure rise using the particle model.[2]
4. (d)State why the compression must be slow for this calculation to be valid.[1]

A runner's skin loses 0.020 kg of sweat by evaporation. The specific latent heat of vaporisation of water is 2 260 000 J/kg.

1. (a)Calculate the energy absorbed from the skin as the sweat evaporates.[2]
2. (b)Explain why this cools the runner.[2]
3. (c)Name the store from which this energy is transferred.[1]

This question is about a hand pump and the air in it.

1. (a)Explain why a pump barrel becomes warm as it is worked rapidly.[2]
2. (b)Air at 250 kPa occupies 0.80 m³. It is compressed slowly to 0.50 m³. Calculate the new pressure.[2]
3. (c)State the condition the compression must satisfy for the calculation in (b) to hold.[1]
4. (d)State the particle-level change that makes the pressure rise.[1]