10. Gas, volume, pressure & temperature

Question 1

What is gauge pressure

Answer 1

pressure value related to the atmospheric pressure and can be positive or negative

Question 2

Zeroth law of thermodynamics

Answer 2

In thermal equilibrium every part of the system has the same temperature

Question 3

Describe the experimental setup for Boyle’s law

Answer 3

• Isothermal - temp did not change

1. system in mechanical eqm
2. seal the tube on the left side - same air pressure (Hg levels equal)
3. add mercury through the open column

The increased weight compresses the sealed gas on the left hand side

Question 4

What happened to the pressure and volume - boyle’s law experiment

Answer 4

• pressure was low and volume high
• mercury was added so pressure increased over time
• volume decreased

Graph is curved

Question 5

What is boyle’s law equation

Answer 5

P1V2 = P2V2

Question 6

Describe experiment for Charles’ Law

Answer 6

Isobaric - the pressure doesn’t change

1. seal the tube on the left hand side, immerse in a solution at room temp
2. increase the temp of the bath. The temperature increases the volume on the left side
3. remove the mercury from the right hand side until mechanical equilibrium

showed V is directly proportional to temperature

Question 7

Ideal gas law

Answer 7

•combined both charle’s and boyle’s laws - PV = nRT

Question 8

Assumptions for an ideal gas

Answer 8

1. Individual volumes of the particles are negligible
2. the gas consists of a very large number of identical particles
3. the particles are in continuous random motion
4. the only form of interaction between the particles or between particles and the container walls are elastic collisions

Question 9

Relation between Ek and P and V

Answer 9

pV = 2/3 Ek

•product of pressure and volume = 2/3 of the kinetic energy stored in the gas