Particle model of matter
Exam-style questions with answers for 4.3 Particle model of matter in AQA GCSE Physics (spec 8463). Practise with flashcards, a topic quiz, a random quiz across the course, 5 crosswords, or read every question and answer below.
All questions and answers
Question 1 · Spec 4.3.1.1 · Density
State the equation for density. [1 mark]
Answer:Density = mass ÷ volume (ρ = m ÷ V).Question 2 · Spec 4.3.1.1 · Density
A block has a mass of 540 g and a volume of 200 cm³. Calculate its density. [2 marks]
Answer:ρ = m ÷ V = 540 ÷ 200 (1); = 2.7 g/cm³ (1).Question 3 · Spec 4.3.1.1 · Density
Convert a density of 1.2 g/cm³ to kg/m³. [1 mark]
Answer:1200 kg/m³.Question 4 · Spec 4.3.1.1 · Particle model
Use the particle model to explain why solids are denser than gases. [2 marks]
Answer:In a solid the particles are closely packed in a regular arrangement (1); in a gas they are far apart, so there is less mass in the same volume (1).Question 5 · Spec 4.3.1.1 · Required practical 5
Describe how to find the density of an irregular object. [3 marks]
Answer:Measure its mass using a balance (1); lower it into a eureka can full of water and collect the displaced water in a measuring cylinder to find its volume (1); calculate density = mass ÷ volume (1).Question 6 · Spec 4.3.1.1 · Required practical 5
Describe how to find the density of a liquid. [2 marks]
Answer:Measure the mass of an empty measuring cylinder, then add a known volume of the liquid and measure the mass again (1); density = mass of liquid ÷ volume (1).Question 7 · Spec 4.3.1.2 · Changes of state
Name the change of state from gas to liquid. [1 mark]
Answer:Condensation.Question 8 · Spec 4.3.1.2 · Changes of state
Name the change of state from solid directly to gas. [1 mark]
Answer:Sublimation.Question 9 · Spec 4.3.1.2 · Changes of state
Why are changes of state described as physical changes? [2 marks]
Answer:The material recovers its original properties if the change is reversed (1); mass is conserved (1).Question 10 · Spec 4.3.2.1 · Internal energy
Define internal energy. [2 marks]
Answer:The total kinetic energy and potential energy of all the particles (1); that make up a system (1).Question 11 · Spec 4.3.2.1 · Internal energy
What happens when a system is heated? [2 marks]
Answer:Its internal energy increases (1); this either raises its temperature or produces a change of state (1).Question 12 · Spec 4.3.2.2 · Specific heat capacity
What does the temperature rise of a substance depend on? [3 marks]
Answer:The mass of the substance (1); what the substance is (its specific heat capacity) (1); the energy put into the system (1).Question 13 · Spec 4.3.2.2 · Specific heat capacity
Calculate the energy needed to raise 0.2 kg of aluminium by 30 °C. c = 900 J/kg °C. [2 marks]
Answer:ΔE = mcΔθ = 0.2 × 900 × 30 (1); = 5400 J (1).Question 14 · Spec 4.3.2.3 · Latent heat
Define specific latent heat. [1 mark]
Answer:The energy needed to change the state of 1 kg of a substance with no change in temperature.Question 15 · Spec 4.3.2.3 · Latent heat
What is the difference between specific latent heat of fusion and of vaporisation? [2 marks]
Answer:Fusion: change of state from solid to liquid (1); vaporisation: change of state from liquid to vapour (1).Question 16 · Spec 4.3.2.3 · Latent heat
Calculate the energy needed to melt 0.5 kg of ice. Specific latent heat of fusion = 334 000 J/kg. [2 marks]
Answer:E = mL = 0.5 × 334 000 (1); = 167 000 J (1).Question 17 · Spec 4.3.2.3 · Latent heat
Calculate the energy needed to boil away 0.2 kg of water at 100 °C. L = 2 260 000 J/kg. [2 marks]
Answer:E = mL = 0.2 × 2 260 000 (1); = 452 000 J (1).Question 18 · Spec 4.3.2.3 · Heating graphs
Why does the temperature stay constant while a substance melts? [2 marks]
Answer:Energy is used to break the bonds between particles (1); so the potential energy increases, not the kinetic energy (1).Question 19 · Spec 4.3.2.3 · Heating graphs
On a heating graph, what do the flat sections show? [1 mark]
Answer:Changes of state (melting or boiling).Question 20 · Spec 4.3.3.1 · Gas particles
Describe the motion of particles in a gas. [1 mark]
Answer:They move in constant random motion.Question 21 · Spec 4.3.3.1 · Gas temperature
How is the temperature of a gas related to its particles? [1 mark]
Answer:The temperature is related to the average kinetic energy of its molecules.Question 22 · Spec 4.3.3.1 · Gas pressure
Explain why increasing the temperature of a gas at constant volume increases its pressure. [2 marks]
Answer:The particles move faster and collide with the container walls more often (1); and with greater force (1).Question 23 · Spec 4.3.3.2 · Gas pressure
Explain how gas particles exert a pressure. [2 marks]
Answer:Particles collide with the walls of the container (1); producing a net force at right angles to the wall (1).Question 24 · Spec 4.3.3.2 · Gas pressure
What happens to the pressure of a fixed mass of gas if its volume is halved at constant temperature? [1 mark]
Answer:The pressure doubles (pV = constant).Question 25 · Spec 4.3.3.2 · Gas pressure
A gas has a pressure of 100 kPa and volume 3 m³. Calculate its pressure if compressed to 1.5 m³ at constant temperature. [2 marks]
Answer:pV = constant: 100 × 3 = p × 1.5 (1); p = 200 kPa (1).Question 26 · Spec 4.3.3.2 · Gas pressure
Why does a gas at a lower volume have a higher pressure? [2 marks]
Answer:The particles are closer together, so they hit the walls more often (1); there are more collisions per second on each area of wall (1).Question 27 · Spec 4.3.3.3 · Work on a gas · Higher only
Explain why pumping up a bicycle tyre makes the pump warm. [2 marks]
Answer:Work is done on the gas when it is compressed (1); this increases the internal energy of the gas, raising its temperature (1).Question 28 · Spec 4.3.3.3 · Work on a gas · Higher only
What is meant by doing work on a gas? [1 mark]
Answer:Transferring energy to the gas by applying a force to compress it.Question 29 · Spec 4.3.1.1 · Density
Calculate the mass of 0.5 m³ of water. Density = 1000 kg/m³. [2 marks]
Answer:m = ρV = 1000 × 0.5 (1); = 500 kg (1).Question 30 · Spec 4.3.1.1 · Density
Why does ice float on water? [1 mark]
Answer:Ice is less dense than liquid water.Question 31 · Spec 4.3.1.2 · Changes of state
Name the change from liquid to gas at the surface at temperatures below boiling point. [1 mark]
Answer:Evaporation.Question 32 · Spec 4.3.1.2 · Conservation of mass
Why does the mass stay the same when ice melts? [1 mark]
Answer:The number of particles does not change; they are just arranged differently.Question 33 · Spec 4.3.2.1 · Internal energy
Explain the difference between temperature and internal energy. [2 marks]
Answer:Temperature depends on the average kinetic energy of the particles (1); internal energy is the total energy of all the particles, so it also depends on mass (1).Question 34 · Spec 4.3.2.2 · Specific heat capacity
Why is water good for storing energy in central heating? [1 mark]
Answer:It has a high specific heat capacity, so it stores a lot of energy for each degree of temperature rise.Question 35 · Spec 4.3.2.3 · Latent heat
Why does steam at 100 °C cause worse burns than water at 100 °C? [1 mark]
Answer:Steam releases extra energy (latent heat) when it condenses on the skin.Question 36 · Spec 4.3.2.3 · Latent heat
State the equation for energy needed for a change of state. [1 mark]
Answer:Energy = mass × specific latent heat (E = mL).Question 37 · Spec 4.3.2.3 · Cooling graphs
Describe what happens to the particles when a liquid freezes. [2 marks]
Answer:The particles lose energy and slow down (1); bonds form so they fix into a regular arrangement (1).Question 38 · Spec 4.3.3.2 · Gas pressure
Why does a balloon expand when warmed? [2 marks]
Answer:The particles move faster, hitting the inside walls harder and more often (1); the pressure inside rises, so the balloon expands until the pressures balance (1).Question 39 · Spec 4.3.3.2 · Gas pressure
State the equation linking pressure and volume for a fixed mass of gas at constant temperature. [1 mark]
Answer:pV = constant.Question 40 · Spec 4.3.1.1 · Particle model
Describe the arrangement and movement of particles in a liquid. [2 marks]
Answer:Close together but randomly arranged (1); free to move past each other (1).Question 41 · Spec 4.3.2.2 · Specific heat capacity
20 000 J is supplied to 1 kg of a substance and its temperature rises by 40 °C. Calculate its specific heat capacity. [2 marks]
Answer:c = ΔE ÷ (mΔθ) = 20 000 ÷ (1 × 40) (1); = 500 J/kg °C (1).Question 42 · Spec 4.3.2.3 · Latent heat
920 000 J is needed to boil 0.4 kg of a liquid. Calculate its specific latent heat of vaporisation. [2 marks]
Answer:L = E ÷ m = 920 000 ÷ 0.4 (1); = 2 300 000 J/kg (1).Question 43 · Spec 4.3.1.1 · Density
Why do gases have a much lower density than solids? [1 mark]
Answer:The particles are spread far apart, so there is much less mass per unit volume.Question 44 · Spec 4.3.1.2 · Changes of state
Name the temperature at which a pure liquid turns to gas. [1 mark]
Answer:The boiling point.Question 45 · Spec 4.3.3.1 · Gas particles
What happens to the speed of gas particles when the gas is cooled? [1 mark]
Answer:The average speed decreases.Question 46 · Spec 4.3.2.1 · Internal energy
Which type of energy of particles increases when a solid is heated below its melting point? [1 mark]
Answer:Kinetic energy (the particles vibrate faster).Question 47 · Spec 4.3.3.2 · Gas pressure
What happens to the volume of a gas if its pressure is tripled at constant temperature? [1 mark]
Answer:It falls to one third.Question 48 · Spec 4.3.1.1 · Density
A stone displaces 25 cm³ of water and has a mass of 75 g. Calculate its density. [2 marks]
Answer:ρ = 75 ÷ 25 (1); = 3 g/cm³ (1).Question 49 · Spec 4.3.1.1 · Particle model
Describe the arrangement and movement of particles in a solid. [2 marks]
Answer:Closely packed in a regular arrangement (1); vibrating about fixed positions (1).Question 50 · Spec 4.3.1.1 · Particle model
Why can gases be compressed but solids cannot? [1 mark]
Answer:Gas particles are far apart with lots of space between them; solid particles are already touching.