Week 2 Day 3 Gas laws

Question 1

Which gas law relates volume and pressure? (Temp is constant)

Answer 1

Boyle’s Law

increased pressure → decreased volume

inverse relationship

“If you compress something, it gets smaller!”

Question 2

According to Charles Law, if you heat something up…..

Answer 2

it expands!

increased temperature → increased volume (pressure constant)

proportional relationship

Question 3

According to Gay-Lussac’s law, if you heat something, what happens to the pressure?

Answer 3

the pressure increases!

increased temperature → increased pressure

Question 4

What does Avogadro’s law tell us about equal volumes of gases at the same temperature and pressure, in regards to # of particles?

Answer 4

equal volumes of different gases have the same # of particles

Question 5

According to Avogadro’s Law, if we add more particles, what happens to volume?

Answer 5

volume gets bigger!

increased particles → increased volume

Question 6

Measure of the degree of saturation of H20 in the air

Answer 6

relative humidity

Question 7

Dew point

Answer 7

point at which water condenses

because warm air holds more water than cool air, so as air cools, it is possible for the amount of water in the air to exceed solubility → condensation

Question 8

Name the 4 assumptions of the Kinetic Molecular Theory of Gases

Answer 8

1. gas molecules are small compared to the volume of the gas, so we can ignore the size of the molecule

2. gas molecules are in constant, random motion

3. gas molecules show a range of kinetic energies, but the average depends on the temperature

4. gas molecules are not attracted or repulsed from each other, so all collisions are elastic

Question 9

Graham’s Law of Effusion (or Diffusion)

Answer 9

smaller particles move faster!

and heating them up also moves them faster

Question 10

Under what 2 circumstances do real gases not behave like ideal gases?

Answer 10

very high pressure or very low temperature

Question 11

Which 2 assumptions of ideal gases hold true for real gases?

Answer 11

2 and 3

2. gas molecules are in constant, random motion
3. gas molecules show a range of kinetic energies, but the average depends on the temperature.

Question 12

For ideal gases, we assume that (1) gas molecules are small compared to the volume of the gas, so we can ignore the size of the molecule. Why is this not entirely true?

Answer 12

we cannot completely ignore the size of the particles, especially as concentration is increased at high pressure

Question 13

For ideal gases, we assume that (4) gas molecules are not attracted or repulsed from each other, so all collisions are elastic. Why is this not entirely true?

Answer 13

gas particles are very weakly attracted, so if the particles move slowly enough, at very low temperatures, this attraction matters

Question 14

True or False: Real gases approach ideal gas behavior as pressure increases and temperature decreases.

Answer 14

False

Real gases approach ideal gas behavior as pressure decreases and temperature increases.