Kinetic particle model of matter

Air trapped in a closed syringe is compressed gradually by pushing the piston in. The air temperature does not change. Which statement about the air is correct?

Feb/March 2016

Gases are compressible, whereas liquids are not. Which statement accounts for this difference?

Feb/March 2016

The diagram illustrates a fixed amount of gas enclosed in a cylinder. The piston is moved inwards gradually, so the gas is compressed. The gas temperature remains constant. Which graph shows how the pressure and volume of the gas are related?

Feb/March 2016

Fig. 4.1 depicts a balloon positioned beside a window on a bright, warm day. Fig. 4.2 illustrates how the balloon’s volume varies over the course of the day.

Feb/March 2016

A student performs an experiment to investigate how the pressure $p$ and the volume $V$ of a fixed mass of gas are related. The table shows four of her measurement sets.

Feb/March 2016

On a hot day, the air pressure inside a car tyre is higher than it is on a cold day. Why does the pressure become higher on a hot day?

Feb/March 2017

Tiny pollen grains are kept in water suspension. A strong light is directed in from the side. Viewed with a microscope, tiny points of light can be observed moving in an irregular, jittery way. What are the moving points of light?

Feb/March 2017

A substance may be found in three states: solid, liquid or gas. Each of the two statements below gives a description of a change of state. change 1: Molecules get nearer to each other but still move through the substance. change 2: Molecules no longer move through the substance and only vibrate around fixed positions. Which changes of state are described by these statements?

Feb/March 2017

Tiny pollen grains are held in water, and a bright light is directed from the side. When the mixture is viewed under a microscope, little points of light are observed moving in a random, jerky way. What are these moving points of light?

Feb/March 2017

Water may be found as ice, liquid water, or steam. Fig. 6.1 shows how the molecules are arranged in the three states of water.

Feb/March 2017

(i) State two ways in which evaporation differs from boiling. (ii) Give one example of a change of state that does not involve boiling or evaporation.

Feb/March 2017

Fig. 5.1 illustrates the setup used to watch the motion of smoke particles suspended in air inside a box. Lamp light enters the box through a window in one side, and a microscope mounted above a window in the top is used to view the smoke particles.

Feb/March 2018

Which row shows the process of melting?

Feb/March 2019

Gas molecules create pressure when they strike the walls of a container. Which statement is correct?

Feb/March 2019

Complete the statements below by filling each blank with solid, liquid or gas. 1. Change of state X is from ________ to ________. 2. Change of state Y is from ________ to ________.

Feb/March 2019

The particles of a substance in one state of matter are moving about freely in random directions. Their mean speed is rising. What is being described?

Feb/March 2020

A student records the mass of warm water in an open container for two minutes. The container is maintained at a constant temperature. The findings are shown in the table. Why does the mass of the water alter?

Feb/March 2020

When pollen grains suspended in water are observed under a microscope, they are seen moving continuously and quickly in random directions. What makes a pollen grain move like this?

Feb/March 2020

Place one tick in each row to show whether the statement describes a gas or a solid.

Feb/March 2020

Air inside a sealed syringe is compressed gradually by pushing the piston in. Its temperature remains unchanged. Which statement about the air is correct?

Feb/March 2021

In an experiment, smoke particles are held in air and observed using a microscope. The smoke particles move with brief random motions. Which of the following statements is correct?

Feb/March 2021

A beaker containing a liquid is heated gradually until the liquid evaporates. While evaporation is happening, from which part of the liquid do the molecules with the greatest energy escape?

Feb/March 2021

In a laboratory, there is a lump of ice that is melting at $0^\circ\text{C}$ and a beaker containing boiling water. The laboratory temperature is $20^\circ\text{C}$. What happens to the temperature of the melting ice, and what happens to the temperature of the boiling water?

Feb/March 2021

Air in a syringe that is sealed is compressed gradually by pushing the piston in. The air temperature remains unchanged. Which statement about the air is correct?

Feb/March 2021

In an experiment, smoke particles are held in air and observed using a microscope. The smoke particles make short, random movements. Which of the following statements is correct?

Feb/March 2021

Using the momentum of molecules, explain how a gas produces pressure on the walls of its container.

Feb/March 2021

Which statement explains what happens to air particles when air is heated?

Feb/March 2023

What occurs when the temperature of a liquid rises?

Feb/March 2023

A gas sample is enclosed in a rigid container. When the gas temperature is raised, the pressure rises. Which statement is not correct?

Feb/March 2023

Fig. 4.1 illustrates some gas at room temperature inside a cylinder fitted with a piston that can move. The gas is trapped and cannot leave the cylinder.

Feb/March 2023

Which statement explains what occurs to particles as a liquid evaporates?

Feb/March 2024

Which row gives the correct description of particle movement in solids and liquids?

Feb/March 2024

When pollen grains suspended in water are observed under a microscope, they can be seen moving continuously, quickly and at random. What makes a pollen grain move like this?

Feb/March 2024

A circular dish with a flat base contains $100\,\text{cm}^3$ of water. The students are asked to suggest ways to make the water evaporate more quickly. Their ideas are given below. Student 1: Transfer the water into a flat-bottomed dish with a greater diameter. Student 2: Reduce the temperature of the dish and the water. Student 3: Use a fan to set up an air current above the dish. Which of these suggestions would raise the evaporation rate?

Feb/March 2024

Matter is made up of extremely small particles that are constantly moving. Which row shows how the particles behave in a liquid?

Feb/March 2024

Which statement gives the correct description of a change of state?

Feb/March 2024

Fig. 5.1 shows a metal container for petrol storage. Some petrol gas is present above the liquid petrol inside the metal container.

Feb/March 2024

The diagram shows a cylinder that contains oxygen at high pressure. The temperature of both the cylinder and the oxygen falls. Which statement explains what happens to the pressure inside the cylinder and states the reason for the change in pressure?

Feb/March 2025

Which statement explains what takes place during solidification?

Feb/March 2025

When solids are heated, they expand the ......1...... and the mean distance between molecules becomes ......2...... . Which words complete the statement about how solids expand when compared with liquids and gases?

Feb/March 2025

A girl inflates a party balloon by blowing air into it, then knots it to keep the air trapped inside. She places the sealed balloon above a hot convector heater. She notices that the balloon’s volume rises greatly. Which statement explains the reason for this increase in volume?

Feb/March 2025

The graph illustrates how the density of a substance changes as its temperature varies with time. Which term names the change of state occurring at time $t_2$?

Feb/March 2025

A sample of gas is enclosed in a container with a fixed volume. Its temperature is raised. Which statement accounts for the increase in the gas pressure?

Feb/March 2025

A fixed mass of gas is enclosed in a sealed syringe at a pressure of $100\,\text{kPa}$. The plunger is then pushed in slowly until the pressure becomes $80\,\text{kPa}$. At that point, the gas has a volume of $50\,\text{cm}^3$. The temperature of the gas remains unchanged. What was the gas volume before the plunger was moved?

Feb/March 2025

The diagram illustrates more energetic water molecules leaving the surface of liquid water. What is this process known as?

Feb/March 2025

Which statement correctly describes evaporation?

May/June 2016

A gas is kept in a sealed container at fixed volume. Its temperature rises. As a result, the pressure of the gas rises. What happens to the gas molecules during this increase in pressure?

May/June 2016

A liquid is undergoing evaporation. It is not at its boiling point. Which statement about the liquid is correct?

May/June 2016

The diagram represents a quantity of gas trapped in a cylinder beneath a piston. The piston may be shifted to the left or to the right. The gas temperature remains constant. Which row gives the effect of moving the piston slowly in the direction indicated in the table?

May/June 2016

Which statement explains what occurs when ice at $0^\circ\text{C}$ begins melting and turns into water?

May/June 2016

What is responsible for the random, zig-zag movement (Brownian motion) of smoke particles suspended in air?

May/June 2016

An airtight bottle with fixed volume contains air. Sunlight warms the air inside the bottle. What happens to the average speed of the air molecules in the bottle, and to the average distance between them?

May/June 2016

A diver underwater is using breathing apparatus at a depth where the pressure is $1.25 \times 10^5\,\text{Pa}$. A gas bubble exhaled by the diver has a volume of $20\,\text{cm}^3$ at the moment it is released. The bubble then rises to the water surface. At the water surface, the atmospheric pressure is $1.00 \times 10^5\,\text{Pa}$. The water temperature is constant at every depth. What volume does the bubble have when it reaches the surface?

May/June 2016

A diver below the water is using breathing apparatus at a depth where the pressure is $1.25 \times 10^{5}\,\text{Pa}$. When the diver releases a bubble of gas, its volume is $20\,\text{cm}^3$. The bubble rises up to the water’s surface. At the surface, the atmospheric pressure is $1.00 \times 10^{5}\,\text{Pa}$. The water temperature is constant at all depths. Determine the volume of this bubble when it arrives at the surface.

May/June 2016

When smoke particles are illuminated by a bright lamp and observed with a microscope, they are seen moving unpredictably. What causes this movement?

May/June 2016

A liquid starts off at a temperature lower than its boiling point. It is then heated until it changes into a gas at a temperature higher than its boiling point. Which row gives the correct comparison between the liquid and the gas?

May/June 2016

A beaker containing a liquid is standing on a laboratory bench. An electric fan in the laboratory produces a draught across the surface of the liquid. The liquid evaporates. Which row shows two changes that would both make the liquid evaporate faster?

May/June 2016

A diver is underwater and using breathing apparatus at a depth where the pressure is $1.25 \times 10^5\,\text{Pa}$. When a gas bubble is exhaled, its volume is $20\,\text{cm}^3$ at the moment it is released. The bubble then rises to the water surface. At the surface, the atmospheric pressure is $1.00 \times 10^5\,\text{Pa}$. The water temperature remains constant at every depth. What volume does the bubble have when it gets to the surface?

May/June 2016

What causes smoke particles suspended in air to move in a random, zig-zag pattern (Brownian motion)?

May/June 2016

An airtight bottle with a fixed volume contains air. The Sun heats the air in the bottle. What effect does this have on the average speed of the air molecules in the bottle, and on the average separation between them?

May/June 2016

Fig. 6.1 illustrates an experiment used to observe how smoke particles move in air.

May/June 2016

A student is examining a mixture of water and ice, with both at the same temperature. He is using a thermometer.

May/June 2016

Explain, in terms of molecules, why a gas can be compressed, but a liquid cannot.

May/June 2016

State what happens to the gas molecules in a sealed container when the gas temperature is raised.

May/June 2016

Within an industrial process, a gas already under high pressure is held inside a large cylinder by a piston. The piston is forced further into the cylinder. While the gas pressure changes, its temperature stays constant.

May/June 2016

Brownian motion can be seen by using a microscope to observe smoke particles in air. What makes the smoke particles move randomly?

May/June 2017

Which change is meant by evaporation?

May/June 2017

The diagram shows molecules of a gas in a sealed container with a fixed volume. What occurs to the molecules of the gas when the container is heated?

May/June 2017

Brownian motion can be seen when a microscope is used to observe smoke particles in air. What makes the smoke particles move randomly?

May/June 2017

Brownian motion can be seen with a microscope when smoke particles are viewed in air. What makes the smoke particles move randomly?

May/June 2017

Pressure is produced on the wall when gas molecules hit the inside surface of a container. Which statement explains this?

May/June 2017

Brownian motion can be seen under a microscope when smoke particles are viewed in air. What makes the smoke particles move randomly?

May/June 2017

Brownian motion can be seen with a microscope when examining smoke particles in air. What is responsible for the random movement of the smoke particles?

May/June 2017

Fig. 6.1 shows workers pouring liquid metal.

May/June 2017

Fig. 5.1 shows a quantity of gas trapped in a metal cylinder beneath a piston.

May/June 2017

A balloon holds a fixed mass of gas.

May/June 2017

Fig. 6.1 presents a child letting go of a helium-filled balloon. The helium pressure inside the balloon is what keeps it expanded.

May/June 2017

Air is enclosed in a cylinder by a piston. The piston is then driven inwards, so the volume of the air decreases. The temperature of the enclosed air stays constant. Which row shows how the average speed of the air molecules and the average distance between them change?

May/June 2018

Which row shows the correct name for each change of state illustrated?

May/June 2018

Brownian motion is the irregular movement of particles caused by collisions with molecules. In which states of matter is Brownian motion seen?

May/June 2018

The diagram illustrates the relative number of molecules in a liquid with a particular kinetic energy. The graph is split into sections so that each section contains the same number of molecules. From which section does the largest number of molecules escape from the liquid per unit time?

May/June 2018

Brownian motion of particles is observed. Which statements describe how the particles move?

May/June 2018

A pure liquid is placed in an open beaker, and some of its molecules leave the liquid by evaporation. Which statement about this process is correct?

May/June 2018

When gas molecules bounce off the side of a container, a pressure acts on the wall. What causes this pressure?

May/June 2018

As gas molecules bounce off the inside surface of a container, a pressure acts on the wall. What causes this pressure?

May/June 2018

When gas molecules bounce back from a container wall, the wall is subjected to pressure. What causes this pressure?

May/June 2018

Describe and explain what the student observes when the smoke particles are viewed through the microscope.

May/June 2018

Describe how the molecules move in a solid.

May/June 2018

Fig. 4.1 shows an atom.

May/June 2018

A microscope with very high magnification is used to view the Brownian motion of smoke particles in air. Fig. 5.1(a) shows the apparatus set up with the microscope. Fig. 5.1(b) shows the view through the microscope and one of the smoke particles being observed.

May/June 2018

Why is it easy to compress a gas into a reduced volume?

May/June 2019

As a liquid evaporates, some of its molecules leave the liquid. The temperature of what is left changes. What happens to the temperature, and from where do the molecules leave?

May/June 2019

The diagram illustrates the changes of state P, Q, R and S that take place in solids, liquids and gases as they gain or lose thermal energy. What is the name of change R?

May/June 2019

As water evaporates, what leaves the water’s surface?

May/June 2019

Which row gives the description of condensation?

May/June 2019

At room temperature, iron is hard to compress. At that same temperature, oxygen is much easier to compress. Which structural difference between iron and oxygen explains this?

May/June 2019

A beaker of water will evaporate if it is left on a bench for some time. Raising the surface area of the water and raising its temperature each affect the rate of evaporation. Which row is correct?

May/June 2019

A liquid-in-glass thermometer is inserted into some ice made from pure water. The ice is heated, so it melts into water and then becomes steam. The graph in Fig. 6.1 shows how the temperature changes with time. The temperature readings are missing from the y-axis.

May/June 2019

A student sets a balloon containing air beside a window, as illustrated in Fig. 4.1. The Sun heats the air inside the balloon.

May/June 2019

Matter exists in three states: solid, liquid and gas.

May/June 2019