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

6.79 atm

Step-by-step 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.