Ideal Gases

Question 1

Combined Gas Law

Answer 1

• Combination of Gay-Lussac’s, Boyle’s, and Charles’ Law
• The product of pressure and volume of a gas is divided by its absolute temperature if the amount of gas is constant
  P1V1/T1= P2V2/T2

Question 2

Changing amount of gas

Answer 2

• Consider: 1 mol of gas with a constant T and P in a container with a moveable top
• When T and P are constant, V and n are directly proportional
• The more moles you have, the volume is increased (to keep pressure constant)

Question 3

Avogadro’s Law

Answer 3

• A constant of V and n
• constant= V/n
• V1/N1= V2= N2

Question 4

The Ideal Gas Law

Answer 4

Combination of Gay-Lussac’s, Boyle’s, Charles’, and Avogadro’s Law
constant/R = PV/ nT
PV= nRT

Question 5

Value of R

Answer 5

• The constant of an ideal gas is R, which has the name universal gas constant
• Units of R must be the exact values used

Question 6

Characteristic of ideal gas

Answer 6

1. Entities have high translational energy, moving randomly in all directions in straight lines
2. When entities collide with each other or the walls of the container the collisions are perfectly elastic (no loss in kinetic energy)
3. The volume of the ideal gas entity is insignificant (close to zero) compared to the volume of the container
4. There are no attractive or repulsive forces between the gas entities
5. They do not condense into liquids when cooled

Question 7

Imaginary standards

Answer 7

• The ideal gas is just an imagery standard
• It is a convenient approximation/model to predict behavior of gases
• At normal conditions, most gases obey the laws pretty well and their resemble an ideal gas

Question 8

Boundaries of Ideal Gas Laws: Temperature

Answer 8

*Gases behave ideal at high temperatures
High temp → most amount of kinetic energy, particles are moving fast with translational energy
* When the temperature decreases, the entities move slowly and get closer together, increasing attractive forces

Question 9

Boundaries of Ideal Gas Laws: Pressure

Answer 9

• Gases behave ideal at low pressures
  Low pressure → most amount of space they can occupy
• When pressures get high, the volume is smaller. The particles become closer together and the attractive forces between the entities becomes more significant
  Gases must have low attractive forces

Question 10

Molar Volume of STP and SATP

Answer 10

• One mol of any ideal gas at STP will be 22.4 L
• Same for SATP