Gas Laws

Atmospheric pressure at sea level in Pa, kPa, atm, mmHg, Torr, Pounds per square inch, Bar

What percentage of air is made up of what components

Nitrogen = 78%

Oxygen = 21%

CO2 = 0.033%

Water vapour, krypton, argon, … make up the rest

Universal Gas Law formula & units

P = Pa

V = m³

n = No. of moles

R = 8.31 (ideal gas constant)

T = Kelvin (°C + 273)

Boyle’s Law words

At a constant temperature, the pressure exerted by a constant number of gas molecules is inversely proportional to volume of the container

(Boyle is constantly boiling hot!)

Boyle’s Law formula

Volume and the number of moles of a gas are ______ proportional

directly

Volume and temperature of a gas are ______ proportional

directly

Volume and the pressure of a gas are ______ proportional

inversely

P ∝ 1​/V

Charles’ Law words

The volume of a gas at a constant pressure varies directly with absolute temperature at a constant pressure

Charles’ Law formula

What is BTPS correction & what does it do

BTPS = conditions within the lungs (body temperature, pressure, water vapor saturation)

Converts flow and volume measured at ambient conditions to the conditions within the lungs

(BTPS = Body Temperature and Pressure, Saturated)

Ambient conditions

Called ATP (ambient temp & pressure)

Ideal gas law formula

Dalton’s Law

The total pressure of a mixture of gases is the sum of the partial pressures of each gas

Is the % of oxygen compared to other components greater, lesser or the same as at sea level compared to the top of Everest

There is still the same % of oxygen at the top of Everest, but partial pressure is reduced so total oxygen volume is reduced

Water vapour percent in inspired, alveolar & expired air

Inspired: 0.5%

Alveolar: 6.2%

Expired: 6.2%

Henry’s Law

When a gas under pressure comes in contact with a liquid, it dissolves in the liquid until equilibrium is reached

(the greater the partial pressure, the greater the amount that will dissolve)

Rank these in order of solubility: CO2, O2, N2