chapter 9 kmm

Question 1

Why do dust particles appear to be floating in the air?

Answer 1

1. fluid particles (eg air particles) move about random and quickly
2. bombard the dust particles

Question 2

Pressure-Temperature relationship

Answer 2

1. temp increases = KE of particles increase
2. particles move at higher speed
3. particles collide into walls more forcefully and more frequently
4. force per unit area increase = P increase
5. P of fixed mass of directly proportional to temp at constant vol

Question 3

Vol-Temp relationship

Answer 3

–> involves piston
1. temp increase = KE of particles in piston increase
2. particles move at higher speed = collide with walls more forcefully and more frequently
3. force acting per unit area increase = internal pressure increase
5. internal pressure greater than atm P = pushes plunger outwards
6. force still high (due to high temp) but area also increases = internal P starts to decrease
7. internal P back to normal = internal P equal to atm P
8. pistol still pushed outwards = vol increases
9. vol of fixed mass of gas directly proportional to temp at constant P

Question 4

Pressure-Vol Relationship

Answer 4

1. volume of container decreases (eg balloon) = no of particles per unit volume decrease
   2a. distance between particles per unit area and walls of container decrease = collide with walls more frequently
   (2b. not more forcefully - no gain in temp - no gain in KE)
2. force per unit area increase
3. P increases
4. P of fixed mass of gas is inversely proportional to its vol at const temp