5.19 Boyle's Law

· 5.19 use the relationship between the pressure and volume of a fixed mass of gas at constant temperature:

p1V1 = p2V2

p1 = Pressure at the beginning [kPa, bar or atm]

V1 = Volume at the beginning [m3 or cm3]

p2 = Pressure at the end [kPa, bar or atm]

V2 = Volume at the end [m3 or cm3]

(Note: can use any units for V and p as long as they are the same at the beginning and end)

5.19 Boyle's Law demos

02 November 2011

20:01

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Fun with the vacuum pump!
· Marshmellows
· Food colouring in pipettes
· Surgical gloves

5.19 Ideal graph and conclusion

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5.19 Experiment

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5.18

Cloud formation
· Place a little water in the bottom of a 1½ litre plastic bottle
· Squeeze a few times
· Introduce a small amount of smoke
· Squeeze and release several times
· When you squeeze, the cloud disappears; when you release, the cloud reforms

Explanation
· When the pressure increases the temperature increases and vica versa
· The smoke particles are nucleating sites on which the water can condense

5.18 Gay-lussac's law

11:11
· 5.18 use the relationship between the pressure and Kelvin temperature of a fixed mass of gas at constant volume:

p1 / T1 = p2 / T2

p1 = Pressure at the beginning [kPa, bar or atm ]

T1 = Absolute temperature at the beginning [K]

p2 = Pressure at the end [kPa, bar or atm]

T2 = Absolute temperature at the end [K]

(Note: the units of temperature must be Kelvin, not oC! The units of pressure can be any, as long as the same at the beginning and the end)

5.18 Ideal graph and conclusion

09 November 2011

15:15
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5.18 Question

Collins, p.116

[cid:image002.jpg@01CCA464.D69055D0]

p1 p2
------ = ------
T1 T2

p1 = 3
T1 = 293
T2 = 328
p2 = 3.36 Bar

a. If we cool the gas in a rigid, sealed tin can, what happens to the pressure inside the can? (1 mark) It will Decrease
b. Explain your answer to part a. by using the Kinetic Theory (4 marks) As the Temperature decreases in the container and volume stays the same, the pressure will decrease as the particles will move slower so they will not hit the walls of the container as hard

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5.18

________________________________________
From: Matt Baker
Sent: Wednesday, November 16, 2011 1:37 PM
To: Andrew Koomenjoe Nyaga; Arisara Amrapala; Boondaree Chang; Chrischawit Chomsoonthorn; Christopher Lo; Connor Blair Sailes; Frazer Allen Briggs; Huei-Yu Daniel Lo; Isabel Catriona McDonald; Kavin Supatravanij; Luke Michael Gebbie; Lydia Anna Foley; Morrakot Sae-Huang; Puchawin Borirackujarean; Qing Tang; Sanyam Grewal; Sebastien Grimm; Soo Hyun Lee; Tatiksha Singh; Usa Wongsanguan; Yanida Areekul; Yi-Lin Huang
Subject: 5.18

5.17 Demo

02 November 2011

19:56

Cloud formation
· Place a little water in the bottom of a 1½ litre plastic bottle
· Squeeze a few times
· Introduce a small amount of smoke
· Squeeze and release several times
· When you squeeze, the cloud disappears; when you release, the cloud reforms

Explanation
· When the pressure increases the temperature increases and vica versa
· The smoke particles are nucleating sites on which the water can condense

5.18 Gay-lussac's law

28 October 2011

11:11
· 5.18 use the relationship between the pressure and Kelvin temperature of a fixed mass of gas at constant volume:

p1 / T1 = p2 / T2

p1 = Pressure at the beginning [kPa, bar or atm ]

T1 = Absolute temperature at the beginning [K]

p2 = Pressure at the end [kPa, bar or atm]

T2 = Absolute temperature at the end [K]

(Note: the units of temperature must be Kelvin, not oC! The units of pressure can be any, as long as the same at the beginning and the end)

5.18 Ideal graph and conclusion

09 November 2011

15:15
[cid:image001.png@01CCA464.D69055D0]

5.18 Question

07 November 2011

15:08

Collins, p.116

[cid:image002.jpg@01CCA464.D69055D0]

P1 P2
------ = ------
T1 T2

P1 = 3
T1 = 293
T2 = 328
P2 = 3.36 Bar a. If we cool the gas in a rigid, sealed tin can, what happens to the pressure inside the can? (1 mark) It will Decrease b. Explain your answer to part a. by using the Kinetic Theory (4 marks) As the Temperature decreases in the container and volume stays the same, the pressure will decrease as the particles will move slower so they will not hit the walls of the container as hard

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5.17

Why do the eggs get sucked into the bottles?!

Explanation
· The burning paper in the bottle heats the air in the bottle
· When the egg gets placed on top, the oxygen supply in the bottle is rapidly depleted and the paper goes out
· The bottle is sealed by the egg and now has a constant volume of gas inside
· The hot gas in the bottle now starts to cool which reduces the pressure inside the bottle
· The pressure outside the bottle remains unchanged and so there is now an unbalanced force on the egg which accelerates the egg into the bottle

· 5.17 describe the qualitative relationship between pressure and Kelvin temperature for a gas in a sealed container

: http://phet.colorado.edu/en/simulation/gas-properties

· Put 5 pumps of gas in
· Set volume as the Constant Parameter
· Heat to 1000K
· Watch what happens to the Pressure

Conclusion
· If you increase the temperature, you increase the pressure

Video - Egg sucked into a bottle by Guy-Lussac's Law.flv Watch on Posterous

5.18 Gay-lussac's law

5.18 use the relationship between the pressure and Kelvin temperature of a fixed mass of gas at constant volume:

p1 / T1 = p2 / T2

p1 = Pressure at the beginning [kPa, bar or atm ]

T1 = Absolute temperature at the beginning [K]

p2 = Pressure at the end [kPa, bar or atm]

T2 = Absolute temperature at the end [K]

(Note: the units of temperature must be Kelvin, not oC! The units of pressure can be any, as long as the same at the beginning and the end)

5.18 Ideal graph and conclusion

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Untitled

Ideal Gas - temperature vs average KE of particles blank table.xlsx Download this file

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Ideal Gas - temperature vs average KE of particles blank table-1.xlsx Download this file

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physics Questions.docx Download this file

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Untitled

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5.14

5.14 describe the Kelvin scale of temperature and be able to convert between the Kelvin and Celsius scales

Converting Centigrade to Kelvin
TK = ToC + 273

Converting Kelvin to Centigrade
ToC = TK - 273

TK = Temperature in Kelvin [K]

ToC = Temperature in Degrees Centigrade [oC]

· Collins p.118

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1. T absolute zero (- 273 degrees centigrade) is when kinetic energy is at zero and the particles are not moving, you cannot go past this point as the particles cannot lose anymore energy as there is non left. 2. a) 20°C = 293K, ii) 150°C = 423K, iii) 1000°C = 1273°C
b) 300K = 27°C ii)650K= 377°C iii) 1000K = 727°C

5.13

18:17
· How can you fit a giraffe, 2 dogs and a swan into a standard laboratory beaker?!

5.13 Starter 2

02 November 2011

18:17

· Use particle theory to explain why the gas in the balloon contracts

Explanation
· The temperature of the gas inside the balloon decreases so the average speed of the particles decreases
· Consequently the gas particles collide with the walls of the balloon with less force and less collisions per second
· Because the walls of the container are flexible, the volume decreases

5.13 Charles' law

28 October 2011

11:10
· 5.13 understand that there is an absolute zero of temperature which is –273oC

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Open the Charles' law interactive experiment
· Adjust the temperature
· What’s the relationship between temperature and volume?
· Plot a graph of V against T
· Take a screen shot of the graph

5.13 results and conclusion

28 October 2011

11:10
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Conclusion
· Volume is directly proportional to absolute (Kelvin) temperature
· V α T

Charles' law interactive experiment.swf Download this file

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5.11

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· You're looking at smoke particles in air under a microscope
· They appear to be jiggling about
· Why?

· (Don't worry if you can't work this out straight away - Albert Einstein was the bloke who eventually explained what's happening here!)

5.11

28 October 2011

11:10
· 5.11 understand the significance of Brownian motion

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Model 1
· What does the red puck represent?
· What do the metal balls represent?
[cid:image001.png@01CC9989.A14EFF60]

[cid:image002.png@01CC9989.A14EFF60]

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Model 3
· What do the "smoke" particles look like?
· Why are they moving?
· What do the "air" particles look like?

5.11 explained

28 October 2011

11:10

Model 1
· What does the red puck represent?
o The large, visible smoke particle
· What do the metal balls represent?
o The small, not visible air particles

Model 2
· What do the small red particles represent?
o The small, not visible air particles
· What does the large blue particle represent?
o The large, visible smoke particle
· What does the view on the left of the screen represent?
o The view through the microscope lense
· Why can‘t you see the red particles in this view?
o They are too small to see

Model 3
· What do the "smoke" particles look like?
o They are the 5 large, sand coloured particles
· Why are they moving?
o Small, fast moving air particles are colliding with the smoke particles and making them move
· What do the "air" particles look like?
o They are the numerous, small, white particles

5.11 Questions

02 November 2011

17:21
1. Draw the path of a smoke particle in air (3 marks) Away from the air ----> they are pushed in whatever the direction the air particles move 2. Explain what is meant by Brownian Motion of smoke particles in air and how it provides evidence for air particles (4 marks)
Brownian motion of smoke particles is the random movement of particles, and this provides eidenc as The smoke particle has a jerky motion.
As (invisible) air molecules collide with the smoke particle,
they push it about in different directions at random.
3. What change would you expect to see in the movement of the smoke particles if the air was cooled down? Why? (2 marks)
the movement would slow down as the air particles had less kinetic energy.

brownian_motion.swf Download this file

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5.12+5.15

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Questions
· Why does the needle on the meter move when gas particles are introduced into the box?
· What does the meter measure?

Answers
· The gas particles collide with all of the walls of the container. The wall on the right moves outwards and moves the needle.
· Pressure. The gas particles colliding with the walls makes a force on the walls. The walls have a surface area so the quantity measured is pressure, p=F/A.

5.12+5.15 Questions

02 November 2011

15:55
· 5.12 recall that molecules in a gas have a random motion and that they exert a force and hence a pressure on the walls of the container
· 5.15 understand that an increase in temperature results in an increase in the speed of gas molecules
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Try the animation http://www.lon-capa.org/~mmp/kap10/cd283.htm
1. How do the particles create a pressure?
By bouncing off the walls of their container.
2. If you increase the temperature, how does the movement of the particles change?
the movement of particles gets faster
3. If you increase the temperature, how does the number of collisions per second change?
it increases
4. If you increase the temperature, what does this do to the pressure?
it increases the pressure

5.12+5.15 Plenary

02 November 2011

15:55

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Ideal gases - summary of terms.pptx Download this file