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    A 400 L container at temperature of 4 celsius initially contains 0.25 mol He gas. Molecular hydrogen, which is a gas at 4 celsius is added until total pressure is 9.38*10^-2 atm. What is the partial pressure of the molecular hydrogen in the container?

    © BrainMass Inc. brainmass.com December 24, 2021, 5:03 pm ad1c9bdddf
    https://brainmass.com/chemistry/gas-laws/partial-pressure-25283

    SOLUTION This solution is FREE courtesy of BrainMass!

    Note
    * denotes multiplication
    ^ denotes power

    Volume=V= 400 L
    No of moles=n= 0.25 mol
    Temperature= T= 4 C= 277.15 K =273.15+4

    Ideal gas Law is PV=nRT
    or P=nRT/V
    R= Gas constant= 0.082058 L.atm.mol ^-1K ^-1
    Therefore
    P=Pressure= 0.0142140 atm =(0.25*0.082058*277.15)/400

    Thus the calculation of pressure of Helium is correct

    In a mixture of two gases the total pressure is the sum of partial pressures

    Partial pressure of Helium= 0.0142140 atm
    Total pressure= 0.0938 atm (given)
    Therefore partial pressure of Hydrogen= 0.0795860 atm =0.0938-0.014214

    Answer: 0.0795860 atm

    This can also be obtained in another way

    We know the total pressure of helium and Hydrogen
    From this we can calculate the no of moles of Hydrogen

    Volume=V= 400 L
    Pressure= 0.0938 atm
    No of moles=n= ? mol (To be determined)
    Temperature= T= 4 C= 277.15 K =273.15+4

    Ideal gas Law is PV=nRT
    or n=PV/RT
    R= Gas constant= 0.082058 L.atm.mol ^-1K ^-1
    Therefore
    n=Total no of moles= 1.65 mol =(0.0938*400)/(0.082058*277.15)

    No of moles of Helium (originally)= 0.25 mol
    Therefore no of moles of Hydrogen added= 1.40 mol =1.65-0.25

    Now calculate the partial pressure of hydrogen using the no of moles of hydrogen

    Volume=V= 400 L
    No of moles=n= 1.40 mol
    Temperature= T= 4 C= 277.15 K =273.15+4

    Ideal gas Law is PV=nRT
    or P=nRT/V
    R= Gas constant= 0.082058 L.atm.mol ^-1K ^-1
    Therefore
    P=Pressure= 0.0795980 atm =(1.4*0.082058*277.15)/400

    Which is close to the answer we obtained above (minor difference because of rounding off error)

    This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

    © BrainMass Inc. brainmass.com December 24, 2021, 5:03 pm ad1c9bdddf>
    https://brainmass.com/chemistry/gas-laws/partial-pressure-25283

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