1. Todays lesson (Supplement only) Relate the change in volume of a gas to change in pressure applied to the gas at constant temperature and use the equation pV = constant at constant temperature.

2. Pressure in a gas What is origin of the pressure of a gas? Volunteers please!

3. Pressure in a gas Collisions of the gas particles with the side of a container give rise to a force, which averaged of billions of collisions per second macroscopically is measured as the pressure of the gas

4. Pressure and Volume at constant temp? http://phet.colorado.edu/en/sim ulation/gas-properties

5. pV = constant p 1 V 1 = p 2 V 2 (at constant temp) This is only true for a constant mass of gas at constant temperature.

6. Example Question A packet of crisps has a volume of 200 cm 3 at sea leveL (PRESSURE = 100 KPa). What volume will the packet have on the summit of Mount Everest (Pressure = 30 kPa)?

7. Example Question A packet of crisps has a volume of 200 cm 3 at sea leveL (PRESSURE = 100 KPa). What volume will the packet have on the summit of Mount Everest (Pressure = 30 kPa)? P 1 = 100 kPa, V 1 = 200 cm 3 P 2 = 30 kPa, V 2 = ?

8. Example Question A packet of crisps has a volume of 200 cm 3 at sea leveL (PRESSURE = 100 KPa). What volume will the packet have on the summit of Mount Everest (Pressure = 30 kPa)? P 1 = 100 kPa, V 1 = 200 cm 3 P 2 = 30 kPa, V 2 = ? P 1 V 1 = P 2 V 2 100x200 = 30V 2

9. Example Question A packet of crisps has a volume of 200 cm 3 at sea leveL (PRESSURE = 100 KPa). What volume will the packet have on the summit of Mount Everest (Pressure = 30 kPa)? P 1 = 100 kPa, V 1 = 200 cm 3 P 2 = 30 kPa, V 2 = ? P 1 V 1 = P 2 V 2 100x200 = 30V 2 20000 = 30V 2 V 2 = 20000/30 = 666 cm 3

10. pV = constant p 1 V 1 = p 2 V 2 (at constant temp) Can you answer the questions that Mr Porter is giving you? This is only true for a constant mass of gas at constant temperature.