Dynamics and Space - Weeblylhsphysicsdept.weebly.com/uploads/5/0/0/7/50076843/ee_pt... · Web view61. (Jearl Walker, Flying circus of physics, 4.130) Use your understanding of physics

Homework Booklet

National 5 Physics

Electricity and Energy Part 3

DO NOT write on this booklet.You will be required to return it at the end of the course!

Last updated by AD May 2014 1

Practice questions on Gas Laws and the Kinetic model (From HSDU Higher Pupil Materials Pack)

Pressure

1. Explain why the use of large tyres helps to prevent a tractor from sinking into soft ground.

2. A box weighs 120 N and has a base area of 2 m2. What pressure does it exert on the ground?

3. a) Explain what is meant by the term pressureb) Atmospheric pressure is the measure of the pressure generated by air in the atmosphere at sea level. Explain how the air generates this pressure.c) If atmospheric pressure is 100000 Pa, what force does the air exert on a wall of area 10 m2?

4. A rectangular steel block measures 10 cm × 8 cm × 6 cm and has a weight of 38N.What is the greatest and the least pressure which it can exert on a surface?

5. Estimate the pressure you exert on the floor when you are standing on one foot.

6. (a) A spray can of deodorant contains gas particles that are constantly moving.

ga s

liq u idde o d o ran t

(i) How do the gas particles produce a force on the container walls?

(ii) As the deodorant is used, liquid leaves the can.State how this changes the gas pressure inside the can. Explain your answer.

(b) Heating the deodorant can is dangerous.

(i) What happens to the average speed of the gas particles when the can is heated?

(ii) State how the pressure changes as the can is heated.

7. (a) The diagram shows particles of a gas in a container.The piston can be moved up or down the container.


(i) Describe the motion of the gas particles in the container.

(ii) Explain how the motion of the gas particles produces a pressure inside the container.

(iii) What would happen to the pressure if you pushed the piston downwards?

(b) When the gas in the container is heated the piston moves upwards.Which are the three correct statements?

I. The gas particles get bigger.

II. The mass of gas particles stays the same.

III. The gas particles move faster.

IV. The gas particles move further apart.

V. The temperature of the gas decreases.

(c) During a long car journey, the air pressure in the tyres increases.

Explain why.

8. (a) Use words from the box to complete the sentences about the particles in a gas. Each word may be used once, more than once or not at all.

collide decreases force increases random reaction


At room temperature, the particles in a gas are moving at ......................................

If the gas is in a container, the particles ...................................... with the walls of the

container.

This exerts a .................................on the walls which causes a pressure.

If the gas cools down, the speed of the particles .................................and the

pressure …………………….

(b) The graph shows how the average kinetic energy of the particles in a gas changes with its kelvin temperature.

0 5 0 1 00 1 5 0 2 0 0 2 5 0 30 0 3 50 4 0 0 4 5 0tem p era tu re in k e lv in

aver

age

kine

tic e

nerg

y of

par

ticle

s

(i) Describe how the average kinetic energy changes with the kelvin temperature.

(ii) Mark with an X the position of 0 °C on the temperature scale of the graph.

(iii) What is the average kinetic energy of the particles at a temperature of zero kelvin?

(iv) Describe the motion of the particles at a temperature of zero kelvin.

Pressure and volume (constant temperature)

9. 100 cm3 of air is contained in a syringe at atmospheric pressure (1 x 105 Pa ).If the volume is reduced to a) 50 cm3 or b) 20 cm3 without a change in temperature, what will be the new pressures?

10. If the piston in a cylinder containing 300 cm3 of gas at a pressure of 105 Pa is moved outwards so that the pressure of the gas falls to 8 × 104 Pa, find the new volume of the gas.


11. A weather balloon contains 80 m3 of helium at normal atmospheric pressure of 105 Pa. What will be the volume of the balloon at an altitude where air pressure is 8 × 104 Pa?

12. The cork in a pop-gun is fired when the pressure reaches 3 atmospheres. If the plunger is 60 cm from the cork when the air in the barrel is at atmospheric pressure, how far will the plunger have to move before the cork pops out?

13. A swimmer underwater uses a cylinder of compressed air which holds 15 litres of air at a pressure of 12000 kPa.

(a) Calculate the volume this air would occupy at a depth where the pressure is 200 kPa.

(b) If the swimmer breathes 25 litres of air each minute at this pressure, calculate how long the swimmer could remain at this depth (assume all the air from the cylinder is available).

Pressure and temperature (constant volume)

14. Convert the following celsius temperatures to kelvin.a) -273 °C b) -150 °C c) 0 °C d) 27 °C e) 150 °C

15. Convert the following kelvin temperatures to celsius.a) 10 K b) 23 K c) 100 K d) 350 K e) 373 K

16. A cylinder of oxygen at 27 °C has a pressure of 3 × 106 Pa. What will be the new pressure if the gas is cooled to 0 °C?

17. An electric light bulb is designed so that the pressure of the inert gas inside it is 100 kPa (normal air pressure) when the temperature of the bulb is 350 °C. At what pressure must the bulb be filled if this is done at 15 °C ?

18. a) The pressure in a car tyre is 2.5 × 105 Pa at 27 °C. After a long journey the pressure has risen to 3.0 × 105 Pa. Assuming the volume has not changed, what is the new temperature of the tyre?

b) Explain this increase in pressure.

19. A compressed air tank which at room temperature of 27 °C normally contains air at 4 atmospheres, is fitted with a safety valve which operates at 10 atmospheres.

a) During a fire the safety valve was released. Explain why this happens. b) Estimate the average temperature of the air in the tank when this happened.


60 cm

20. (a) Describe an experiment to find the relationship between the pressure and temperature of a fixed mass of gas at constant volume. Your answer should include:(i) a labelled diagram of the apparatus(ii) a description of how you would use the apparatus(iii) the measurements you would take.

(b) Use the following results to plot a graph of pressure against temperature in °C using axes as shown below.

(i) Explain why the graph you have drawn shows that pressure does not vary directly as celsius temperature.

(ii) Explain how the graph can be used to show direct variation between temperature and pressure if a new temperature scale is introduced.

(iii) Use the graph to estimate the value in °C of the zero on this new temperature scale.

(c) Use the particle model of a gas to explain the following:(i) why the pressure of a fixed volume of gas decreases as its

temperature decreases(ii) why the pressure of a gas at a fixed temperature decreases if its

volume increases(iii) what happens to the molecules of a gas when Absolute Zero is

reached.

21. A sealed cylinder contains air. The pressure of the air is measured at different temperatures.The table shows the results.

Temperature(°C)

Pressure(atmospheres)

–150 0.45

0 1.00

100 1.40

250 1.95

(a) Draw a graph of these results.

(b) Use your graph to find the temperature of the air at which its pressure would be zero.

(c) Suggest why it is not possible to measure the pressure of air at a temperature of –350 °C.


(d) The diagram shows the relationship between the kelvin and Celsius temperature scales.

Te m p e ra tu re in k e lv in

Tem p era tu re in °C

0

– 2 7 3

2 7 3

0

3 7 3

1 0 0

(i) The melting point of ice is 0 °C.Write down the equivalent temperature in kelvin

(ii) Nitrogen boils at a temperature of 77 K.What is the equivalent temperature in °C?

22. An experiment was carried out to measure how the pressure of a gas changes with temperature.The volume and mass of the gas were kept constant throughout the experiment.The following results were obtained.

Pressure in kPa 90 96 103 110 117 123

Temperature in °C 0 20 40 60 80 100

(i) Draw a graph of these results.

(ii) Describe, using the graph, how the pressure of the gas changes with temperature.

(iii) Use your graph to estimate the temperature at which the gas exerts no pressure.

(iv) What name is given to the temperature at which a gas exerts no pressure?

(b) The air pressure in car tyres is higher during a motorway journey then when the car stands in the garage.Explain why.

23. (a) The gas in a container produces a pressure on the container walls.Which statement best explains why this is?

I. The gas particles push each other apart

II. The gas particles are tightly packed together

III. The gas particles keep hitting the sides of the container

IV. The gas particles hit each other as they move about

(b) The temperature of the gas in the container is increased.This causes the pressure to increase.

Which statement best explains why this is?

I. The number of gas particles increases

II. The mass of the gas particles increases

III. The energy of the gas particles increases

IV. The volume of the gas container increasesLast updated by AD May 2014 7

(c) The diagram shows the relationship between the kelvin (K) temperature scale and the Celsius (oC) temperature scale.

K 0 3 7 3

° C – 2 7 3 1 0 0

(i) Use the information shown in the diagram to complete the following.

K = C +

(ii) What temperature on the kelvin temperature scale is equal to 0 oC on the Celsius temperature scale?

(iii) Cold water has a temperature of 293 kelvin.What temperature is this on the Celsius scale?

(iv) What name is given to 0 kelvin?

(d) (i) At 0 kelvin the gas in a container would not produce a gas pressure Explain why.

(ii) What is the state of all matter at this temperature?

24. The pressure of a gas in a sealed container at 20 °C is 100 000 Pa.The container is placed near a source of heat that raises the temperature of the gasto 80 °C.Calculate the new pressure of the gas in the container.

25. The diagram shows a tank of helium gas. The tank has a gauge to measure the pressure of the helium and a sensor to measure the temperature.

h eliu mg aste m p era tu re

se n so r

p ressu re g a u g e


(a) Explain, in terms of its molecules,

(i) how the helium gas exerts a pressure.

(ii) why the pressure of the gas increases with temperature.

(b) The tank of helium gas is brought from an outside storeroom into a warm laboratory.The temperature and pressure of the helium are recorded as the gas warms up to room temperature.

The table shows the results obtained.

temperature (°C) pressure (kPa)

8.0 107.5

10.5 108.5

12.0 109.0

14.0 110.0

18.0 111.5

23.5 113.5

(i) Draw a graph of pressure against temperature.

(ii) Use your graph to find the pressure of the helium at 0 °C.

(iii) Explain why the pressure of the helium at 0 °C is not 0 kPa.

(iv) At what temperature should the pressure theoretically be 0 kPa?

26. The diagram shows the relationship between the kelvin and Celsius temperature scales.

Tem p era tu re in k e lv in

Tem p era tu re in °C

2 7 3

0

0

– 2 73

3 7 3

1 0 0

(a) What temperature is absolute zero:

(i) on the kelvin scale?

(ii) on the Celsius scale?

(b) A gas cylinder contains carbon dioxide at a temperature of 22 °C.

(i) What is the temperature of the carbon dioxide on the kelvin scale?


(ii) The carbon dioxide gas is heated from 22°C to a temperature of 50°C.Copy and place one tick in each row of the table to show the changes that take place to the properties of the gas particles.

particle property decreases stays the same increasemassaverage kinetic energysizeaverage speed

(2)

(iii) Suggest why it could be dangerous to heat the gas cylinder to a temperature greater than 50 °C.

27. Helium gas leaves the reactor at a temperature of 1173 K. Helium gas is pumped into the reactor at a temperature of 500 °C.

(i) What is the temperature in kelvin of the helium gas when it enters the reactor?

(ii) Helium gas enters at a pressure of 8.40 MPa. Calculate the pressure of helium gas as it leaves the reactor. The volume of the gas does not change.

28. Phillip noticed that the tyre became harder as he pumped more air into it.

(a) (i) Explain how the air in the tyre produces a pressure.

(ii) Suggest why the pressure increases when more air is put in.

(b) When Phillip had finished pumping up the tyre, the pressure of the air in it was1.70 × 105 Pa.

During a long journey, the temperature of the air in the tyre increases from 18°C to 22°C.

Calculate the new pressure of the air in the tyre, assuming the tyre volume did not change.


Volume and temperature (constant pressure)

29.Describe an experiment to find the relationship between the volume and temperature of a fixed mass of gas at constant pressure. Your description should include:

(a) a diagram of the apparatus used(b) a note of the results taken(c) an appropriate method to find the relationship using the results.

30.100 cm3 of a fixed mass of air is at a temperature of 0 °C. At what temperature will the volume be 110 cm3 if its pressure remains constant.

31.Air is trapped in a glass capillary tube by a bead of mercury. The volume of air is found to be 0.10 cm3 at a temperature of 27 °C. Calculate the volume of air at a temperature of 87 °C.

32.The volume of a fixed mass of gas at constant temperature is found to be 50 cm3. The pressure remains constant and the temperature doubles from 20 °C to 40 °C. Explain why the new volume of gas is not 100 cm3.

33. Sarah used the apparatus below to investigate what happens to the volume of a gas when the pressure is reduced while the temperature stays the same.

w e ig h ts

s tro n g co rd

p u lley s

L u b rica te w ithv a cu u m g rease

L a rg e g a s sy rin g e(c ap p ed )

Sarah took readings of the volume as she added weights (loading) and as she removed the weights (unloading).

She recorded the results of her experiment in the table below.


volume of gas in mlpressure in kPa loading unloading average

100 50 50 50

90 56 55 55.5

80 64 63 63.5

70 70 71 70.5

60 85 83 84

50 101 101 101

(a) Suggest why she took two sets of readings for the volume.

(b) Plot a graph of her average volume against pressure.

(c) Use the particle model to explain why the pressure of a gas increases when the volume decreases.

(d) Sarah was careful to keep the temperature constant during her experiment.State and explain what would have happened to the pressure readings if she had allowed the temperature of the gas to increase.

34. Zoë is investigating what happens to the volume of a gas when its temperature is increased.The diagrams show the equipment that she uses.

20

15

10

5

0

12

11

10

cm

100

90

80

70

60

50

40

30

20

10

0

th e rm o m ete r

b ea k e r

sca le to m e asu re v o lu m e o f g a s

tra p p ed g as b e in g te s ted

tu b e o p e n to a tm o sp h e re


The graph shows her results.

–

–

–

–

–

–

–

–

–

–

–

–

– ––––––tem pe ra tu re in °C

1 2 .0

11 .0

1 0 .0

9 .0

8 .0

7 .0

6 .0

5 .0

4 .0

3 .0

2 .0

1 .0

0 .00 2 0 4 0 6 0 8 0 1 0 0

v o lu m eo f g as

(a) Tick ( ) the three statements that are true for Zoë’s investigation.

statement true?as the temperature increases the volume increases

as the temperature increases the pressure increases

the mass of the gas is constant

the pressure of the gas is constant

when the temperature in °C doubles the volume doubles

(b) Complete each sentence below

(i) When a gas is heated its particles …

(ii) When a gas is heated its particles hit the walls of the container …

(iii) The kinetic energy of the particles of a gas is directly proportional to …

(c) State the value of 100°C in kelvin.

(d) What happens to the movement of particles when the temperature is absolute zero?


General gas equation

35.Given, for a fixed mass of gas, p α T and p α 1/V, derive the general gas equation.

36. Find the unknown quantity from the readings shown below for a fixed mass of gas.

(a) p1 = 2 × 105 Pap2 = 3 × 105 Pa

V1 = 50 cm3

V2 = ?T1 = 20 °CT2 = 80 °C

(b) p1 = 1 × 105 Pap2 = 2.5 × 105 Pa

V1 = 75 cm3

V2 = 100 cm3T1 = 20 °CT2 = ?

(c) p1 = 2 × 105 Pap2 = ?

V1 = 60 cm3

V2 = 80 cm3T1 = 20 °CT2 = 150 °C

(d) p1 = 1 × 105 Pap2 = 2.5 × 105 Pa

V1 = 75 cm3

V2 = 50 cm3T1 = ?T2 = 40 °C

37.A sealed syringe contains 100 cm3 of air at atmospheric pressure 105 Pa and a temperature of 27 °C. When the piston is depressed the volume of air is reduced to 20 cm3 and this produces a temperature rise of 4 °C. Calculate the new pressure of the gas.

38.Calculate the effect the following changes have on the pressure of a fixed mass of gas.

(a) Its temperature (in K) doubles and volume halves.(b) Its temperature (in K) halves and volume halves.(c) Its temperature (in K) trebles and volume quarters.

39.Calculate the effect the following changes have on the volume of a fixed mass of gas.(a) Its temperature (in K) doubles and pressure halves.(b) Its temperature (in K) halves and pressure halves.(c) Its temperature (in K) trebles and pressure quarters.

40.Explain the pressure-volume, pressure-temperature and volume-temperature laws qualitatively in terms of the kinetic model.

41. Mei-li works on engine design in a specialist combustion laboratory.Her job involves testing different fuel-air mixtures.

She has to:

mix a fuel gas with air

measure its temperature, volume and pressure

compress the mixture

measure its temperature, volume and pressure just before ignition.

These are her results.

before after

pressure 1.01 × 105 Pa 23.8 × 105 Pa

volume 14 cm3 2 cm3

temperature 27 °C

Calculate the temperature of the mixture just before it ignites and state its unit.


Open Ended Questions for Gas Laws

42. 2 identical containers are connected by a narrow tube that has a control valve. Initially, all the liquid is in the left container. What may happen if you release the control valve and why?

43. It's a very hot summers day. You want to cool the house so you leave the fridge open. Will this work?

44. Comment on this statement by an anonymous scientist: “things get worse under pressure”.

45. When tending to an open fire, if you turn a log around that has been burning on one side but not the other, can often make the room feel very warm. Use your knowledge of physics to comment on this.

46. Use your knowledge of physics to comment on why when water pipes freeze there is a danger of them bursting when the water changes back to a liquid.

47. Bakers add yeast to bread dough to produce bubbles of carbon dioxide (CO2).

Using your knowledge of physics, explain why this causes the dough to rise in an oven.

48. Using your knowledge of physics explain why it is dangerous to put an aerosol can in a fire.

49. Using your knowledge of physics, comment on the claims made by the “Go Anywhere” type company in the above below.

50. Using your knowledge of physics estimate the pressure exerted on the floor when you stand on two feet. You must clearly state all assumptions made .

51. Some cosmetic companies are reducing the size of aerosol canisters in order to reduce costs. They claim that the same quantity of deodorant is contained within the new smaller canisters.

Use your understanding of Physics to comment on these claims.

52. A skier has a safety helmet which is fitted securely and comfortable using an air cushion system. The skier fastens the helmet to their head at the bottom of the mountain and inflates the air cushion inside the helmet to secure the helmet in place. Having travelled up to the top of the mountain comment on the adjustments (if any) that should be made to the helmet in order for it to remain securely but comfortable in place.


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National 5 Section 1 Exam Style Questions for Gas Laws

53. (Qn 7 Higher Physics 2008)





58. (Qn 7 Higher Physics 2012

National 5 Section 2 Exam Style Questions for Gas LawsLast updated by AD May 2014 16


(c) The number of particles x 1023, n, contained within one balloon can be calculated using the ideal gas law equation:

The symbols p, V and T have their usual meaning and are measured in standard units.

How many particles of helium are contained within one balloon if it is filled at a temperature of 293K?

(d) A large fully filled helium balloon is connected as shown to a partially filled balloon of the same size. The helium inside is free to flow between the two balloons. Which balloon, if either, is bigger in the end? Justify your answer.


Fully filled balloon

Partially filled balloon


(ii) The distance, d, in meters that a gas particle can travel before colliding with another gas particle can be calculated using the formula:

Where w is the width of the gas particle in meters.

Show by calculation whether oxygen (particle width 3.6 x 10-10 m) or helium (particle 1.5 x 10-

10 m) will collide more often when contained in a gas cylinder.

61. (Jearl Walker, Flying circus of physics, 4.130)

Use your understanding of physics to explain why you should try to lie down if you find your self sinking into quick sand.



(b) When the student begins to dive under water their body will experience an increase due to the weight of the water above them. The total pressure, P, in Pa experienced by the student diver can be calculated using the formula:

Where pa in Pa is the pressure due to the atmosphere above the water (an average 1 x 105 Pa), ρ is the density of the water in kgm-3 and d in meters is the depth to which the diver has reached under water.

Water Density (Kgm-3)Fresh water 1,000Sea water 1,035

(i) Use the formula above and your understanding of Physics to explain why the total pressure experienced by a diver in sea water would be greater than the total pressure experienced by a diver at the same depth in fresh water.


(ii) Calculate the depth under sea water to which the diver can dive if they are not to exceed double the atmospheric pressure on any given day.



(a) Using your understanding of Physics explain how an inverted glass of water can hold up a cardboard base?

(b) How is the trick affected if a long glass tube of water is used instead of the glass? (Does it still work? Can it hold even heavier cardboard?...)


water

cardboard

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Practice questions on Gas Laws and the Kinetic theory (From HSDU Higher Pupil Materials Pack)

1. Large tyres mean a larger surface area. This means for the same force (the weight of the tractor) there is less pressure on the ground.

2. 60 Pa

3. a) force per unit area

b) When air particles bump into objects they exert a force (F) on them. Since this force is generated over an area (A) this generates a pressure (P). P = F/A

c) 1 x 106 N

4. 7917 Pa, 4750 Pa

5. something in the 10’s of thousand’s Pa

6. (a) (i) An explanation to include two from:1. molecules are moving / have (kinetic) energy;2. colliding with container walls;3. each collision produces a force;

(ii) An explanation to include:1. molecules moving faster / more (kinetic) energy / moving more;2. colliding more often with the walls / harder collisions / more force;

(b) (i) all points plotted correctlystraight line of best fit;

(ii) straight line extended to pressure axis; pressure of 104.5 ± 0.3 kPa;

(iii molecules still have energy (to move) / molecules still moving;

(iv) –273°C / 0 K / absolute zero;

7. (a) (i) A description to include:

1. particles moving;

2. in all directions/randomly / or implied by description (each other / walls);

(ii) An explanation to include:

1. particles hit/collide with container walls;

2. producing a force;

(iii) pressure would increase/get bigger/larger;

(b) statements 2, 3 and 4 ticked Last updated by AD May 2014 22

(c) An explanation to include two from:

1. temperature of air in tyre increases / hot / hotter;

2. particles hit more often/hit harder;

3. particles moving faster / more energy;

8. (a) random;collide;force;decreases;decreases;

(b) (i) A description to include:1. increases;2. uniformly / equally / steadily / in a straight line /

positive correlation

(ii) X on temperature axis between 250 and 300 K

(iii) zero;

(iv) not moving;

9. a) 2 x105 Pa b) 5 x105 Pa

10. 375 cm3

11. 100 m3

12. 40 cm

13. a) 900 litres b) 36 minutes

14. a) 0 K, b) 123 K, c) 273 K, d) 423 K

15. a) -263 oC, b) -250 oC, c) -173 oC, d) 77 oC, e) 100 oC

16. 2.73 x106 Pa

17. 4.6 x104 Pa

18. a) T = 87 °C.

b) Friction between the tyre and road causes the tyre and gas inside to be heated up. As the gas is heated to a higher temperature the particles speed up and mean kinetic energy of the particles increases. This means that the air particle hit the insides of the tyre more often and with a greater force. Since the inside surface area of the tyre remains unchanged according to P = F/A the pressure inside the tyre must increase.

19. a) During a fire the air in the tank is heated. As the gas is heated to a higher temperature the particles speed up and mean kinetic energy of the particles increases. This means that the air particle hit the insides of the tank more often and with a greater force. Since the inside surface area of the tank remains unchanged according to P = F/A the pressure inside the tank must increase. When the pressure inside the tank reaches 10 atmospheres a large enough force is exerted by the gas on the safety valve to push open the safety valve and release particles of air from the tank reducing the pressure inside.


b) T = 477 °C.

20. a) see your teacher for the answer to this question

b) (i) the line of best fit does not pass through the origin (0,0)

(ii) temperature scale on the x-axis should be in Kelvin, the results would then show a straight line od best fit that passes through the origin

(iii) approx -300 °C

c) (i) As the temperature decreases the speed and resulting mean kinetic energy of the particles decreases. The particles then hit the sides of the container less often and with less force (F). If the surface area (A) of the container remains the same then due to P = F/A the pressure inside the container must decrease.

(ii) As the volume of a container increases the surface area (A) inside the container also increases. If the temperature is unchanged than the force (F) exerted by the particles when they collide with the sides of the container remains unchanged. Due to P = F/A the pressure inside the container must decrease.

(iii) the particles do not move at all, their speed is zero and their mean kinetic energy is zero.

21. (a) four points plotted correctlystraight line drawn

(b) –260 to –280

(c) impossible temperature/this is below absolute zero/pressure is zero/no movement;

(d) (i) 273

(ii) –196

22. (a) (i) points plotted correctlystraight line;

(ii) pressure increases with temperature;

(iii) line back tracked;260 10 oC;

(iv) absolute zero/ 0 K;

(b) An explanation to include: tyres get hot/increase in temperature; air expands/more collisions/air particles inside move more

/have more KE

23. (a) gas particles keep hitting the sides of the container;


(b) energy of the gas particles increases;

(c) (i) 273;

(ii) 273;

(iii) 293 – 273;= 20°C;

(iv) absolute zero;

(d) (i) An explanation to include:1. has no energy/particles not moving;2. no collisions;

(ii) solid/frozen;

24. P2 = 120 478 (Pa);

25. (a) (i) An explanation to include two from:1. molecules are moving / have (kinetic) energy;2. colliding with container walls;3. each collision produces a force;

(ii) An explanation to include:1. molecules moving faster / more (kinetic) energy / moving more;2. colliding more often with the walls / harder collisions / more force;

(b) (i) all points plotted correctlystraight line of best fit;

(ii) straight line extended to pressure axis; pressure of 104.5 ± 0.3 (kPa) / value from their graph;

(iii) molecules still have energy (to move) / molecules still moving;

(iv) –273°C / 0 K / absolute zero;

26. (a) (i) 0;

(ii) – 273;

(b) (i) 295;

(ii)particle property decreases stays the same increases

mass average kinetic

energy

size average speed

(iii) the pressure would increase the cylinder could explode;


27. (i) 773(K)

(ii) 12.7 (MPa)

28. (a) (i) (particles) collide with tyre wall;

(ii) more collisions / second

(b) 1.72 × 105 = P2;

29. see your teacher for the answer to this question

30. 300 K

31. 0.012 cm3

32. pressure is not proportional to temperature in °C, pressure is proportional to temperature in K, doubling of temperature in K (not °C ) would lead to double volume

33. (a) Any sensible suggestion eg to produce an average reading/to reduce effect of anomalous results(b) suitable scales; points; curve/line of best fit;

(c) pressure caused by particles hitting walls/number of particles constant;more hits per unit time;

(d) Pressure increased particles would have moved faster;(particles) would hit walls harder;

34. (a)statement True?

as the temperature increases the volume increases

as the temperature increases the pressure increases

the mass of the gas is constant

the pressure of the gas is constant

when the temperature in °C doubles the volume doubles

(b) (i) speed up ;

(ii) more frequently ;

(iii) the temperature in K;

(c) 373 (K)

(d) movement ceases;

Accept:• the particles stop moving /

• no KE• particles at their lowest (vibrational) speed• particles are still• idea of smallest possible movement


35. see your teacher for the answer to this question

36. a) 40 cm3 b) 977 K c) 2.2 × 105 Pa d) 188 K

37. 5.1 × 105 Pa

38. a) pressure increases x 4, b) no change in pressure, c) pressure increases x 12

39. a) volume increases x 4, b) no change in volume, c) volume increases x 12

40. see study guide p9

41. T= 1010 K ( 737 C)


53. D (Qn 7 Higher Physics 2008)

54. C (Qn 7 Higher Physics 2009)

55. A (Qn 6 Higher Physics 2010)

56. C (Qn 5 Higher Physics 2011)

57. A (Qn 7 Higher Physics 2011)

58. E (Qn 7 Higher Physics 2012)



(c) number is 8.5 x 1023

(d) Ask your teacher to mark this question – reasonable answers are likely to include comments on force, area, pressure and air pressure.


(ii) the oxygen particles will collide more often since the distance they travel before collision is less than for helium


Ask your teacher to mark this question – reasonable answers are likely to include comments on force, area and pressure.



(b) (i) At the same depth and under the same atmospheric pressure there is more weight and therefore force (F) due to the sea water than there is due to the fresh water. Since this force is to act on the same diver of area A then since P = F/A the diver would be under more pressure in the sea water.

p fresh water = pa + 9800d

p sea water = pa + 10,143d

(ii) d = 9.8m



a) Ask your teacher to mark this question – reasonable answers are likely to include comments on force, area, pressure and air pressure.

b) Ask your teacher to mark this question – reasonable answers are likely to include comments on force, weight, area, pressure and air pressure.



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Dynamics and Space - Weeblylhsphysicsdept.weebly.com/uploads/5/0/0/7/50076843/ee_pt... · Web view61. (Jearl Walker, Flying circus of physics, 4.130) Use your understanding of physics