11 The Behavior of Gases

Question 1

Boyle’s Law

Answer 1

states that for a given mass of gas at constant temperature, the volume of the gas varies inversely with pressure. The equation involves pressure-volume calculation, and two given pressures and volumes will be equivalent when multiplied (P1 x V1 = P2 x V2; 100 kPa’s at 1 L will be 50 kPa’s at 2 L.)

Question 2

Charles’s law

Answer 2

states that the volume of a fixed mass of gas is directly proportional to its Kelvin temperature if the pressure is kept constant. The equation V1/T1 = V2/T2 is used to express this, where the ratios will always be equivalent. (1 L at 300^K, if turned to 600^K, would become 2 L.)

Be sure to use Kelvin in your equation!

Question 3

The Ideal Gas Law

Answer 3

Allows one to find the moles of a gas at any given pressure, volume, and temperature. The usual form is this: P x V/ T x n = R, R is just a number, called the ideal gas constant

Question 4

ideal gas constant

Answer 4

This number, R, is 8.31 (L x kPa)/(K x mol). The equation for the ideal Gas law is P x V/T x n = R OR P x V = n x R x T

It may be necessary to convert moles to kilograms if the amount of kilograms is what is asked for.

Question 5

partial pressure

Answer 5

the contribution each gas in a mixture makes to the total pressure is the partial pressure of that gas.

In gas mixture the total pressure is the sum of the partial pressures.

Question 6

Dalton’s law of partial pressures

Answer 6

at a constant volume and temperature, the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of the component gases. Ptotal = P1 + P2 + P3