National 5PhysicsSQAExam QuestionsProperties Of MatterGas Laws & The Kinetic Model

Gas Laws & The Kinetic Model (SQA National 5 Physics): Exam Questions

Exam code: X857 75

54 mins18 questions
1
Sme Calculator1 mark

A hammer hits a nail with a force of 5.0 kN.

The pressure exerted by the hammer on the nail is 2.0 space cross times space 10 to the power of 8 Pa.

The area of the nail hit by the hammer is

  • 2.5 space cross times space 10 to the power of negative 8 end exponent space straight m squared

  • 2.5 space cross times space 10 to the power of negative 5 end exponent space straight m squared

  • 4.0 space cross times space 10 to the power of 4 space straight m squared

  • 4.0 space cross times space 10 to the power of 7 space straight m squared

  • 1.0 space cross times space 10 to the power of 12 space straight m squared

Choose your answer

21 mark

A sealed hollow buoy drifts from warm Atlantic waters into colder Arctic waters.

The volume of the buoy remains constant.

The pressure of the trapped air inside the buoy changes because pressure is

  • directly proportional to the temperature in kelvin

  • inversely proportional to the temperature in kelvin

  • inversely proportional to the volume of the air inside the buoy

  • inversely proportional to the temperature in degrees Celsius

  • directly proportional to the temperature in degrees Celsius

Choose your answer

3
Sme Calculator1 mark

The pressure of a fixed mass of gas is 5.0 space cross times space 10 to the power of 5 Pa. The temperature of the gas is 320 K and the volume of the gas is 2.2 m3.

The gas is then heated to a temperature of 370 K and the pressure of the gas increases to 5.5 space cross times space 10 to the power of 5 Pa.

The new volume of the gas is

  • 1.7 m3

  • 2.1 m3

  • 2.3 m3

  • 2.8 m3

  • 4.1 m3

Choose your answer

4
Sme Calculator5 marks

An aircraft is flying at high altitude.

During the flight the pressure of the air inside the aircraft is reduced.

(i) State what is meant by the term pressure.

[1]

(ii) During the flight a passenger notices that the volume of a crisp packet is greater than it was at take‑off.

At take‑off the pressure of the gas inside the crisp packet was 101 kPa and the volume of gas in the crisp packet was 2.3 cross times10−3 m3.

During the flight the pressure of the gas inside the crisp packet is 92 kPa.

The temperature of the gas inside the crisp packet remains constant.

Calculate the volume of the gas inside the crisp packet at a pressure of 92 kPa.

[3]

(iii) Describe how the kinetic model accounts for the pressure of the gas inside the crisp packet.

[1]

How did you do?

5
Sme Calculator1 mark

A cyclist is riding a bicycle along a level road.

A cyclist in motion rides a racing bicycle along a paved path, wearing a helmet and sports attire, with blurred steps in the background.

The combined mass of the cyclist and bicycle is 70.0 kg.

The total contact area between the tyres and the road is 8.0 cross times 10−4 m2.

The average pressure exerted by the tyres on the road is:

  • 1.2 cross times10−6 Pa

  • 5.6 cross times10−2 Pa

  • 8.8 cross times104 Pa

  • 4.3 cross times105 Pa

  • 8.6 cross times105 Pa

Choose your answer

6
Sme Calculator1 mark

The average kinetic energy of a gas molecule can be determined using the following relationship.

E subscript k equals 3 over 2 k subscript B T

where: Ek is the average kinetic energy of a gas molecule in joules, J

kB is Boltzmann’s constant = 1.38 cross times 10−23 J K−1

T is the temperature of a gas molecule in kelvin, K.

The average kinetic energy of a gas molecule at 100 °C is:

  • 2.07 cross times10−21 J

  • 3.58 cross times10−21 J

  • 5.15 cross times10−21 J

  • 5.65 cross times10−21 J

  • 7.72 cross times10−21 J

Choose your answer

7a
Sme Calculator3 marks

A group of students are investigating how the pressure of a fixed mass of gas varies with its temperature. This is known as Gay‑Lussac’s Law.

The students set up an experiment as shown.

Laboratory setup with a round-bottomed flask held by a retort stand, surrounded by a beaker with water, atop a tripod stand with a Bunsen burner.

The round‑bottomed flask contains a fixed mass of gas.

The Bunsen burner is used to heat the apparatus as shown. Readings of temperature and pressure are taken every 10 °C.

During the experiment the volume of the gas in the round‑bottomed flask remains constant.

The students’ results are shown.

Temperature (°C)

Temperature (K)

Pressure (kPa)

50

323

121

60

333

124

70

343

128

80

353

132

Use all the appropriate data to establish the relationship between the pressure and the temperature of the gas.

How did you do?

7b
Sme Calculator1 mark

Predict the pressure of the gas at a temperature of 100 °C.

How did you do?

7c1 mark

Suggest one way the students could improve the experiment.

How did you do?

7d1 mark

The tyre pressure in racing cars is carefully monitored throughout a race.

As the cars drive around the racing circuit, the temperature of the gas inside the tyres increases.

Explain, using the kinetic model, how this affects the pressure of the gas inside the tyres.

How did you do?

8
Sme Calculator1 mark

The pressure p due to a liquid at a depth h is given by the relationship

p equals rho g h

where ρ is the density of the liquid and g is the gravitational field strength.

A liquid has a density of 990 kg m-3.

When the pressure due to the liquid is 1470 Pa, the depth in the liquid is

  • 0·069 m

  • 0·15 m

  • 0·67 m

  • 1·5 m

  • 6·6 m

Choose your answer

91 mark

A car is parked in the sun for some time. During this time the air pressure inside the tyres increases.

The reason for this increase in pressure is

  • the volume occupied by the air particles in the tyres has increased

  • the force produced by the air particles in the tyres acts over a smaller area

  • the average spacing between the air particles in the tyres has increased

  • the increased temperature has made the air particles in the tyres expand

  • the air particles in the tyres are moving with greater kinetic energy

Choose your answer

10
Sme Calculator1 mark

The temperature of a sample of gas in a container is 20 °C.

The volume of the gas is 0·30 m3.

The container is free to expand in order to maintain a constant pressure.

The temperature of the gas is increased to 50 °C.

The volume now occupied by the gas is

  • 0·12 m3

  • 0·27 m3

  • 0·30 m3

  • 0·33 m3

  • 0·75 m3

Choose your answer

11a
Sme Calculator3 marks

A water rocket consists of a plastic bottle partly filled with water. Air is pumped in through the water. When the pressure is great enough, the tube detaches from the bottle. Water is forced out of the bottle, which causes the bottle to be launched upwards.

Diagram of a setup showing a bottle with pressurised air and water, connected to a bicycle pump by a tube, illustrating pressure dynamics.

At launch, the air in the bottle is at a pressure of 1·74 cross times105 Pa

The area of water in contact with the pressurised air in the bottle is 4·50 cross times10-3 m2.

Calculate the force exerted on the water by the pressurised air at launch.

How did you do?

11b
Sme Calculator7 marks

At launch, the air in the bottle has a volume of 7·5 cross times10-4 m3.

At one point in the flight, the volume of air in the bottle has increased by 1·2 cross times10-4 m3.

During the flight the temperature of the air in the bottle remains constant.

(i) Calculate the pressure of the air inside the bottle at this point in the flight.

[4]

(ii) Using the kinetic model, explain what happens to the pressure of the air inside the bottle as the volume of the air increases.

[3]

How did you do?

12
Sme Calculator1 mark

A syringe containing air is sealed at one end as shown.

Diagram of a syringe with labelled parts: plunger, air, syringe, and seal, illustrating its structure and function in a medical context.

The initial volume of the air in the syringe is 1.40 cross times10−6 m3 and the pressure is 120 kPa.

The plunger is pushed in causing the volume to be reduced by 0.30 cross times10−6 m3.

The temperature of the air inside the syringe remains constant.

The pressure of the air inside the syringe is now

  • 26 kPa

  • 94 kPa

  • 99 kPa

  • 153 kPa

  • 560 kPa

Choose your answer

13a
Sme Calculator6 marks

A cyclist inflates the tyres on their bike before going cycling.

Person inflating a bicycle tyre using a hand pump; wearing a watch, focusing on the wheel with blurred background.

The cyclist inflates a tyre to a pressure of 655 kPa.

The temperature of the gas inside the tyre is 21 °C.

At one point in the journey the temperature of the gas inside the tyre is 14 °C.

The mass of gas and the volume of gas inside the tyre remain constant.

(i) Determine the pressure of the gas inside the tyre at a temperature of 14 °C.

[3]

(ii) Explain, using the kinetic model, how the decrease in temperature affects the pressure of the gas inside the tyre.

[3]

How did you do?

13b4 marks

At one point, the cyclist stops pedalling and freewheels.

Silhouette of a cyclist wearing a helmet, riding a road bike with drop handlebars, in a forward-leaning position on a white background.

The tyres have a total contact area with the ground of 7.5 cross times10−4 m2 and exert a pressure of 1.02 cross times106 Pa on the ground.

Determine the total mass of the cyclist and bike.

How did you do?

14
Sme Calculator1 mark

The pressure of the air outside an aircraft is 0·40 cross times105 Pa.

The air pressure inside the aircraft cabin is 1·0 cross times105 Pa.

The area of an external cabin door is 2·0 m2.

The outward force on the door due to the pressure difference is

  • 0·30 cross times105 N

  • 0·70 cross times 105 N

  • 1·2 cross times 105 N

  • 2·0 cross times 105 N

  • 2·8 cross times 105 N

Choose your answer

15
Sme Calculator1 mark

A solid at a temperature of −20 °C is heated until it becomes a liquid at 70 °C.

The temperature change in kelvin is

  • 50 K

  • 90 K

  • 343 K

  • 363 K

  • 596 K

Choose your answer

16
Sme Calculator1 mark

A sealed bicycle pump contains 4·0 cross times10−5 m3 of air at a pressure of 1·2 cross times105 Pa.

The piston of the pump is pushed in until the volume of air in the pump is reduced to 0·80 cross times10−5 m3.

During this time the temperature of the air in the pump remains constant.

The pressure of the air in the pump is now

  • 2·4 cross times104 Pa

  • 1·2 cross times105 Pa

  • 1·5 cross times105 Pa

  • 4·4 cross times105 Pa

  • 6·0 cross times105 Pa

Choose your answer

172 marks

During the flight the aircraft uses fuel.

Explain why the pressure exerted by the tyres of the aircraft on the runway after the flight is less than the pressure exerted by the tyres on the runway before the flight.

How did you do?

18a
Sme Calculator7 marks

A student sets up an experiment to investigate the relationship between the pressure and temperature of a fixed mass of gas as shown.

Diagram of an experimental setup showing a glass flask with gas in water, connected to pressure and temperature sensors and a temperature meter.

The student heats the water and records the following readings of pressure and temperature.

Pressure (kPa)

101

107

116

122

Temperature (K)

293

313

333

353

(i) Using all the data, establish the relationship between the pressure and the temperature of the gas.

[3]

(ii) Using the kinetic model, explain why the pressure of the gas increases as its temperature increases.

[3]

(iii) Predict the pressure reading which would be obtained if the student was to cool the gas to 253 K.

[1]

How did you do?

18b2 marks

State one way in which the set-up of the experiment could be improved to give more reliable results.

Justify your answer.

How did you do?