3.1 Properties of Gases Flashcards
What is the kinetic theory of gases?
Gases are a collection of molecules moving randomly around in space
Pressure is generated by collisions of molecules with a surface
The more frequent and harder the collisions, the higher the pressure generated by the gas
What is the ideal gas equation?
Describes properties of gases
P= nR.T/V
What is Boyle’s Law?
Pressure of a gas is inversely proportional to its volume
P ∝ 1/V
What will the total pressure exerted be in a mixture of non-reacting gases?
The sum of the partial pressures of the individual gases
What is atmospheric pressure?
The pressure exerted by the weight of the air above the earth in the atmosphere
What is atmospheric pressure at sea level and how will this change at high altitudes?
101kPa = 1 atmosphere
Lower at high altitudes
Why is atmospheric pressure lower at high altitudes?
Less air pressing down
How do you work out partial pressure of a gas in atmospheric air?
101 X Percentage composition
What is Saturated Vapour Pressure?
6.28kPa
It’s when water molecules leave and enter water at the same rate meaning that the air is saturated with vapour
Where in the respiratory tract does inhaled air become saturated with water?
Upper respiratory tract
How do you work out the partial pressure of gases in moist air?
Pressure of the rest of the gases = 101 - 6.28 = 94.7 kPa
The other gases are still in the same ratios as in dry air
(101-6.28) x percentage
What is partial pressure?
The pressure exerted by the dissolved gas in the liquid
How do you work out amount of gas dissolved?
Amount = Partial pressure x Solubility coefficient of gas
What is pO2?
Measure of O2 dissolved in the blood
Define partial pressure
Pressure exerted by the dissolved gas in a liquid
