Mixtures of helium and oxygen are used in scuba diving tanks to help prevent the bends, which is a condition caused by nitrogen bubbles forming in the bloodstream. If 75 L of oxygen and 25 L of helium at STP are pumped into a scuba tank with volume of 8.0 L, what is the partial pressure of helium in the tank?

Question

Quizplus · Accepted Answer

The partial pressure of a gas is equal to the mole fraction of that gas multiplied by the total pressure. The mole fraction of helium is 25 L / (75 L + 25 L) = 0.25. The total pressure is 8.0 L / 22.4 L/mol = 0.355 atm. Therefore, the partial pressure of helium is 0.25 * 0.355 atm = 0.08875 atm.

Mixtures of Helium and Oxygen Are Used in Scuba Diving