Gas Phase

Question 0

Ideal Gas

Answer 0

Volume-less gas with no intermolecular forces used in calculations that behaves according to the kinetic molecular theory of gases as described by the ideal gas law.

Question 1

STP

Answer 1

273.15 K
1 atm = 760 mm Hg = 760 torr

Not to be confused with standard state!

Question 2

What are the assumptions inherent in the Kinetic Molecular Theory of Gases?

Answer 2

• Volume-less particles
• Constant, random motion
• No intermolecular attractions
• Perfectly elastic collisions
• Average kinetic energy proportional to absolute temperature of gas

Question 3

Ideal Gas Law

Answer 3

PV = nRT

Question 4

Boyle’s Law

Answer 4

Pressure is inversely proportional to Volume at constant Temperature.

PV = k

Question 5

Gas Constant

Answer 5

8. 21 X 10^-2 (L•atm)/(mol•K)

8. 34 J/(K•mol)

Question 6

Charles and Gay-Lussac’s Law

Answer 6

Volume is directly proportional to its Temperature at a constant Pressure.
V/T = k

Question 7

Avogadro’s Principle

Answer 7

The number of moles present is directly proportional to the Volume of the gas at constant Temperature and Pressure. One mole of gas has a volume of 22.4 L.
n/V = k

Question 8

How does the behavior of Real Gases differ from that of Ideal Gases as Pressure increases to condensation pressure?

Answer 8

As the pressure increases, particles are pushed closer together and intermolecular forces become stronger as the gas becomes a liquid.

Question 9

At moderately high pressures (a few hundred atm), what happens to a real gas?

Answer 9

The volume will be less than that expected from the ideal gas law.

Question 10

What happens to the Volume of a real gas at extreme pressures?

Answer 10

The molecules begin to expand, increasing the volume.

Question 11

What happens to real gases as temperature decreases?

Answer 11

The average velocity decreases, leading to a smaller Volume, as the Temperature approaches the condensation point and intermolecular forces become stronger, forming a liquid.

Question 12

Van der Waald equation

Answer 12

(P + ((a*n^2)/V^2))(V - nb) = nRT
a corrects for the attractive component
b corrects for the volume

Question 13

Vapor Pressure

Answer 13

A vapor’s partial pressure when in equilibrium with its liquid and solid state.

Question 14

Partial Pressure or Dalton’s Law of Partial Pressures

Answer 14

(Pressure of single gas) = (Total Pressure) (mole fraction of single gas)

mole fraction = (number of moles of gas)/(total number of moles)

Sum of partial pressures equals total pressures

Question 15

Henry’s Law

Answer 15

Dissolved gas pressure is directly proportional to gas partial pressure above solution.

Question 16

Average speed of gases

Answer 16

|v| = (3RT/MM)^1/2

Question 17

Kinetic Energy and Temperature of gas

Answer 17

KE = (1/2)mv^2 = (3/2)(Boltzmann’s Constant) T

Question 18

Graham’s Law

Answer 18

R1/R2 = (MM2/MM1)^1/2

For effusion and diffusion

Question 19

Diffusion

Answer 19

Passive transport through a medium due to random motion.

Question 20

Effusion

Answer 20

Movement of a gas through a small opening to an area off lower pressure.