5.18 Answer

From: Matt Baker
Sent: Tuesday, November 22, 2011 10:18 AM
To: Amaris Odermatt; Churaimas Diskul; Hannah Amanda Fotheringham; Janyaporn Buaboos; Jarouwit James; Khuntup Issara; Oliver Thomas Bailey; Tamara Nikki Davies
Subject: 5.18 Answer

 

 

5.18 Answer

07 November 2011

15:08

Collins, p.116

 

 

a.              If we cool the gas in a rigid, sealed tin can, what happens to the pressure inside the can? (1 mark)

The pressure will decrease

 

b.             Explain your answer to part a. by using the Kinetic Theory (4 marks)

·         The volume remains the same because a tin can is a rigid container

·         If the temperature decreases the gas molecules have a lower average Kinetic Energy

·         So there are less collisions between the gas molecules and the walls of the container per second

(NB: Can also say that slower molecules will collide with less force) (1 mark)

·         So the pressure in the container will decrease

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5.17

5.17 starter

	<<Video - Egg sucked into a bottle by Guy-Lussac's Law.flv>>

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

28 October 2011

11:11

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

Instructions

·         Launch the application on this website: 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

 

 

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 "cloud" is water droplets - liquid water

·         When you squeeze the bottle the temperature increases and the droplets turn into water vapour

·         The smoke particles are nucleating sites on which the water can condense

FW:

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

5.16 Virtual Experiment

 

 

5.16 Virtual Experiment

28 October 2011

11:11

·         5.16 understand that the Kelvin temperature of the gas is proportional to the average kinetic energy of its molecules

 

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