Helium is mixed with oxygen gas for deep-sea divers. calculate the percent by volume of oxygen gas in the mixture if the diver has to submerge to a depth where the total pressure is 3.8 atm. the partial pressure of oxygen is maintained at 0.20 atm at this depth.

Answer : The percent by volume of oxygen gas in the mixture is, 5.3 %

Explanation :

According to the Raoult's law,

where,

= total partial pressure of solution = 3.8 atm

= partial pressure of oxygen = 0.20 atm

= mole fraction of oxygen = ?

Now put all the given values in this formula, we get:

Now we have to calculate the percent by volume of oxygen gas in the mixture.

The mole percent of oxygen gas =

As we know that, there is a direct relation between the volume of moles.

So, mole percent of oxygen gas = volume percent of oxygen gas

Volume percent of oxygen gas =

Therefore, the percent by volume of oxygen gas in the mixture is, 5.3 %