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    Molecular formula of Nitrogen and Hydrogen molecule

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    A compound contains only nitrogen and hydrogen and is 87.4% nitrogen by mass. A gaseous sample of the compound has a density of 0.977 g/L at 710. torr and 99.9°C. What is the molecular formula of the compound?

    © BrainMass Inc. brainmass.com December 24, 2021, 8:23 pm ad1c9bdddf
    https://brainmass.com/chemistry/stoichiometry/molecular-formula-nitrogen-hydrogen-molecule-271558

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    Molecular formula of Nitrogen and Hydrogen molecule given pressure, temp, density and percent by mass

    A compound contains only nitrogen and hydrogen and is 87.4% nitrogen by mass. A gaseous sample of the compound has a density of 0.977 g/L at 710. torr and 99.9°C. What is the molecular formula of the compound?

    Solution:
    mass of nitrogen=87.4 g
    moles of nitrogen=87.4 g × (1 mol)/(14.01 g)
    =6.2384 mol

    mass of hydrogen=100 g- 87.4 g
    =12.6 g
    moles of hydrogen=12.6 g × (1 mol)/(1.01 g)
    =12.475 mol

    (moles of hydrogen)/(moles of nitrogen)=12.475/6.2384
    =1.9997
    =2

    PV=nRT
    P/RT=n/V
    P/RT=mass/(V×M)
    PM/RT=mass/V
    PM/RT=d

    (710 torr × (1 atm)/(760 torr)×M)/(0.08206 (L atm)/(K mol) ×(99.9+273.15)K)=0.977 g/L
    (0.9342 atm ×M)/(0.08206 (L atm)/(K mol) ×373.05 K)=0.977 g/L
    M=(0.977 g/L ×0.08206 (L atm)/(K mol) ×373.05 K)/(0.9342 atm)
    =32.01 g/mol
    Empirical molar mass = (14.01 + 2 × 1.01) g/mol
    = 16.03 g/mol

    Ratio = 32.01 / 16.03 = 2

    Therefore, the molecular formula is N2H4.

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

    © BrainMass Inc. brainmass.com December 24, 2021, 8:23 pm ad1c9bdddf>
    https://brainmass.com/chemistry/stoichiometry/molecular-formula-nitrogen-hydrogen-molecule-271558

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