Chem geniuses, i need some help

Discussion in 'Pre-Medical - MD' started by WorkOnIt, Nov 15, 2002.

  1. WorkOnIt

    WorkOnIt Junior Member

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    ! I need some help from my fellow chem geniuses. This is the prob. that has me stuck:

    The effusion rate of an unknown gas is measured and found to be 31.50 mL/min. Under identical expermential conditions, the effusion rate of O2(oxygen) is found to 30.50 mL/min. If the choices are CH4, CO, NO, CO2, and NO2, what is the indentity of the unknown gas?

    My book says the answer is NO. but i dont see how the answer is obtain. what steps and equation are used???
     
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  3. BrainDrain

    BrainDrain Member

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    just plug into formula:

    Effusion Rate O2/Effusion Rate X=square root(Mol.W X/MW O2)

    squared(30.5/31.5)=Mol.W X/32

    Mol.W X=30

    which is the Mol. Wt. of NO


    Hope you can understand this:)
     
  4. WorkOnIt

    WorkOnIt Junior Member

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    thanks for reply. it took me a min., but i got it. but just to be sure :), this is how u would do it, right:

    squared(30.5/31.5)=Mol.W X/32

    976= 31 Mol. W X

    976/31.5=30.9 but i guess u can take NO since its the nearest 30. if thats how u do it, sorry but i'm just a bit of a perfectonist :D
     
  5. BrainDrain

    BrainDrain Member

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    The answer is EXACTLY 30.

    squared(30.5/31.5)=Mol.W X/32

    squared(0.968)=Mol.W X/32

    0.9375 X 32=Mol.W

    Mol. W=30.00
     
  6. WorkOnIt

    WorkOnIt Junior Member

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    oh, i see. thanks
     

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