Industrial deep-sea divers must breathe a mixture of helium and oxygen to prevent a disorienting condition known as nitrogen narcosis.

Industrial deep-sea divers must breathe a mixture of helium and oxygen to prevent a disorienting condition known as nitrogen narcosis. If a diver's tank is filled with a helium-oxygen mixture to a pressure of 170 atmospheres and the partial pressure of helium is 110 atmospheres, the partial pressure of the oxygen is