lesson 2

Question 1

the kinetic molecular theory of gases.

Answer 1

based of of speculation:

• the particles size doesn’t matter
• the pressure is caused by constant motion.
• the particles don’t affect each other.
• assumed to be proportional temperature in Kalvin.

Question 2

why does the size of particles not matter?

Answer 2

because it is so small that it makes no significant difference.

Question 3

How KMT model explains properties of gas. pressure and volume from Boyle’s law.

Answer 3

decrease in volume means an increase in particles hitting the walls and increasing pressure.

Question 4

How the KMT model explains properties of the gas. pressure and temperature from Boyle’s law

Answer 4

as the temperature of gas increase, the speed of particles increase causing an increase in the force of particles hitting the walls & frequency leading to an increase in pressure.

Question 5

How KMT model explains properties of gas. volume and temperature according to Charles’s law.

Answer 5

the gas is heated, the speed of particles increases leading to an increase in pressure and so the pressure can stay constant is to increase the volume.

Question 6

How KMT model explains properties of gas. number of moles and volume.

Answer 6

to increase number of particles without increasing the pressure, we need to increase volume.

Question 7

How KMT model explains properties of gas. Dalton’s law.

Answer 7

size of particles doesn’t matter so sum of each gas added together.

Question 8

how to derive ideal gas law?

Answer 8

P = 2/3 [ n*N*(1/2*mu^2) / V ] => (KE)ave = N*(1/2*mu^2)
P = 2/3 [ n*(KE) / V ] -> VP / n = 2/3 KE ~~ T

Question 9

Molecular Speed

Answer 9

Root mean square velocity

u(Root mean square) = u ^2/2 = ( 3RT / N*m)^(1/2)

Question 10

speed distribution is affected by temperature.

Answer 10

the Maxwell-Boltzmann distribution -> as temperature increases, the range & value become higher.

Question 11

deviation of real gas (pressure)

Answer 11

in ideal gas: P = 1 atm in all conditions.

real gas: PV/nRT is approaches 1 only at very low pressure.

Question 12

deviation of real gas (temperature)

Answer 12

real gas approaches the state of ideal gas as temperature increase.

Question 13

when does real gas behave closer to ideal gas?

Answer 13

at lower pressure and higher temperature.

Question 14

modification to KMT to explain the behavior of real gas.

Answer 14

• the size of particles as the volume is affected by it.
• the attraction between particles makes the observed pressure smaller than ideal.
  > the correction factor is calculated w/ N^2/2 which is the number of possible pairs.

Question 15

what is van der Waals equation

Answer 15

[P(obs) + a (n/V)^2] * (V-nb) = nRT

Question 16

according to the van der Waals equation, how does high pressure affect the volume of particles significance?

Answer 16

as pressure increases, the volume of particles becomes more significant because they have less room to move.

Question 17

according to the van der Waals equation, how does high temperature affect the significance of the interaction between particles.

Answer 17

practically insignificant as the particles move quicker.

Question 18

when does a gas liquify?

Answer 18

when pressure is decreased and the temperature drops turning it from gas to liquid.

Question 19

what is critical temperature?

Answer 19

the temperature that gas starts to liquify.