3. Properties of gases

Question 1

What is Boyle’s Law

Answer 1

PRESSURE of a gas is directly proportionate to its TEMPERATURE and NO. OF MOLES PER VOLUME, and inversely proportional to its VOLUME.

Question 2

what is the partial pressure of a gas

Answer 2

pressure exerted by a gas when in a mixture of gases, in proportion to its volume percentage in the mixture (Dalton’s Law)

Question 3

what is the solubility coefficient of a gas

Answer 3

amount of a gas (in mmol) that will dissolve in a litre of plasma at 37°C when exposed to a given partial pressure

amount of gas dissolved = solubility coefficient of that gas x partial pressure it is exposed to

Question 4

why does the pO2 of inhaled air change as it moves from nostrils to alveoli

Answer 4

1. inhaled air becomes saturated with water vapour in the upper resp. tract - displaces some oxygen and nitrogen so O2 % drops to about 20% with a drop in kPa to 19.8 (rather than 21.1 kPa)
2. in alveoli, O2 diffuses into capillary blood flowing past to reach equilibrium causing pO2 to drop to 13.3 kPa