chemistry

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A sample of a breathing mixture for divers contained 34.3% helium, He; 51.7% nitrogen, N2; and 14.0% oxygen, O2 (by mass). What is the density of this mixture at 22°C and 748 mmHg?

  • chemistry -

    I would use a modified form of PV = nRT that is P*molar mass = dRT for density.
    You need to calculate the molar mass of the mixture of gases which cn be done by
    0.343 x molar mass He = ??
    0.517 x molar mass N2 = ??
    0.140 x molar mass O2 = ??
    Add. The sum is the molar mass of the mixture. Then substitute the conditions of T and P and solve for density.

  • chemistry -

    I keep getting d=0.00441. I'm not sure what I'm doing wrong. My equation with the numbers substituted in looks like this: (0.98421)(0.10853)=d(0.08206)(295.15)

  • chemistry -

    He gave you the wrong formula.
    I know that this is over a year after you posted, but you should actually just use the formula d=PM(molar mass)/RT.

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