Question

A breathing mixture used by deep-sea divers contains helium, oxygen, and carbon dioxide. what is the partial pressure of oxygen at 101.4 kpa if phe = 82.5 kpa and pco2 = 0.4 kpa?

Answer 1

Pressure of the Mixture = 101.4 kpa  
Pressure of the helium phe = 82.5 kpa 
 Pressure of CO2 pco2 = 0.4 kpa.
 Partial pressure of oxygen = Pressure of the Mixutre - (Pressure of the
helium + Pressure of CO2)
 Partial pressure of oxygen = 101.4 - 82.5 - 0.4
 Partial pressure of oxygen = 18.5 kPa

Answer 2

Answer:

18.5 kPa is the partial pressure of oxygen.

Explanation:

Total pressure of the gases = p =  101.4 kPa

Partial pressure of the helium gas = $p_{He}=82.5 kPa$

Partial pressure of the carbon dioxide gas = $p_{CO_2}=0.4 kPa$

Partial pressure of the oxygen gas = $p_{O_2}=?$

Applying Dalton's law of partial pressure:

$p=p_{He}+p_{CO_2}+p_{O_2}$

$101.4 kPa=82.5 kPa+0.4 kPa+p_{O_2}$

$p_{O_2}=101.4 kPa-82.5 kPa-0.4 kPa=18.5 kPa$

18.5 kPa is the partial pressure of oxygen.