Question

Question #777e2

Answer 1

The pressure is unknown. The partial pressure is a multiple of the mole fraction of each component.

Explanation:

We have volume, and amount of substance; we do not have temperature, which we require if pressure is to be calculated. I assume that the temperature is `298*K`.

`"Moles of helium:"` `(32.6*g)/(4.0*g*mol^-1)=8*mol`

`"Moles of dioxygen:"` `(51.2*g)/(32.0*g*mol^-1)=1.6*mol`

The total pressure `P=(nRT)/V` `=`

`((8.0+1.6)*molxx0.0821*L*atm*K^-1*mol^-1xx298*K)/(0.150*L)` `=` `P_T`

The partial pressure of dioxygen `P_(O_2)=(P_(O_2))/P_T` `=` `(1.6*mol)/((8+1.6)*mol)xxP_T`.

This sounds like a deep sea diving mix, where helium replaces dinitrogen in order to avoid the narcotic effect of dinitrogen.