·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)
Fun with the vacuum pump!·Marshmellows· Food colouring in pipettes· Surgical gloves5.19 Ideal graph and conclusion
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 bottl
e· 5.17 describe the qualitative relationship between pressure and Kelvin temperature for a gas in a sealed containerInstructions
·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
·5.14 describe the Kelvin scale of temperature and be able to convert between the Kelvin and Celsius scalesConverting Centigrade to Kelvin
TK = ToC + 273Converting Kelvin to Centigrade
ToC = TK - 273TK = Temperature in Kelvin [K]ToC = Temperature in Degrees Centigrade [oC]
5.13 Starter·How can you fit a giraffe, 2 dogs and a swan into a standard laboratory beaker?!5.13 Starter 2· 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 decreases5.13 Charles' law28 October 201111:10· 5.13 understand that there is an absolute zero of temperature which is –273oC
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 conclusion28 October 201111:10
Conclusion
· Volume is directly proportional to absolute (Kelvin) temperature· V α T
5.11 Starter
·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· 5.11 understand the significance of Brownian motion
Model 1
· What does the red puck represent?· What do the metal balls represent?
Model 3
· What do the "smoke" particles look like?· Why are they moving?· What do the "air" particles look like?5.11 explained28 October 201111:10Model 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 particles5.11 Questions1. Draw the path of a smoke particle in air (3 marks)2. Explain what is meant by Brownian Motion of smoke particles in air and how it provides evidence for air particles (4 marks)3. What change would you expect to see in the movement of the smoke particles if the air was cooled down? Why? (2 marks)
5.12+5.15 Starter. Watch the video and think about the question. No need to type anything.This e-lesson consists of 3 objectives; 5.12, 5.15 and 5.11. I’ll e-mail the other objective separately.Instructions for Objective 5.12 and 5.151.
2. 5.12+5.15 Questions. Open the animation. Forward this e-mail to your blog and complete the questions.
3. 5.12+5.15 Plenary. Open the attached ppt. View as slide show. Think about what the blanks in the table are. Check your answers with slide 2. No need to type anything.
4. Answers to step 2 will be sent separately. Don’t look at them until you’ve done the work!
Best wishes,Mr B5.12+5.15 Starter
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·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
Because gas molecules are moving around at random motion, they eventually collide into the wall of the container, exerting force on its surface.http://www.lon-capa.org/~mmp/kap10/cd283.htmTry the animation
1. How do the particles create a pressure?
The speed of the movement of gas molecules increases due to the increase in average kinetic energy.2.If you increase the temperature, how does the movement of the particles change?
The collisions per second increases.3.If you increase the temperature, how does the number of collisions per second change?
The pressure increases due to the increase in kinetic energy, which increase the collision of gas molecules to the wall. As a result, more force is being exerted onto the wall of the container and therefore pressure increases.4.If you increase the temperature, what does this do to the pressure?
5.12+5.15 Plenary<<Ideal gases - summary of terms.pptx>>
