Question

Human lungs have evolved to breathe oxygen at a pressure as that in the atmosphere, 0.21 atm. If a particular heliox mixture to be carried by a scuba diver is at a pressure of 7.00 atm, what should be the partial pressure due to helium in order to maintain the pressure due to oxygen at 0.21 atm?

Answer 1

Answer:

6.79 atm

Explanation:

Applying Dalton's law of partial pressure:

$P_{total} = P_{helium} + P_{oxygen}$, where $P_{total}$ = total partial pressure of all the component gases in the mixture, $P_{helium}$ = partial pressure of helium gas, and $P_{oxygen}$ = partial pressure of oxygen gas.

From the illustration, $P_{total}$ = 7.00 atm and $P_{oxygen}$ = 0.21 atm. Hence, the partial pressure due to helium is calculated such that:

$P_{helium}$ = $P_{total} - P_{oxygen}$

           = 7.00 - 0.21

              = 6.79 atm

Therefore, the partial pressure due to helium in order to maintain the pressure due to oxygen at 0.21 atm would be 6.79 atm.