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General chemistry questions

Discussion in 'Pre-Dental' started by ibo man, Aug 28, 2002.

  1. ibo man

    ibo man Senior Member
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    I will appreciate i if I could get help with this few general chemistry questions. I don't why I couldn't figure out how they got the answers.
    1) A 49 gram sample of sulfuric acid, H2SO4 (98g/mol), contains
    A. 1 mol of S atoms.
    B. 16.0 grams of O.
    C. 2.0 grams of H.
    D. 2 moles of O atoms.
    E. I mole of molecules.
    The correct answer to the above question is D.

    2) If 1 mole of N2 (nitrogen gas) and 1 mole of H2 (hydrogen gas) are mixed and allowed to react according to the equation N2+3H2 ---> 2NH3, the maximum number of moles of NH3 that could be produced is
    A. 2/3.
    B. 3/2.
    C. 2/1.
    D. 1/2.
    E. 1/1.
    The correct answer to the above question is A.

    I will appreciate it very much if I could get some help :confused:
     
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  2. DATMATT

    DATMATT SISU
    7+ Year Member

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    1. 49g(1 mol/98g)= 0.5 molH2SO4

    0.5 mol H2SO4(4 mol of O atoms/1 mol H2SO4)= 2 mol O atoms

    2. N2+3H2 ---> 2NH3

    1 mol of H2 limits the product. (if you used 1 mol of N2 you would still be short 2 moles of H2)

    Also, for every 2 mols NH3 made, 3 mols of H2 are used

    1 mol H2(2 mol NH3/3mol H2)= 2/3 mol NH3 made

    Hopes this helps....

    Matt
     
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  3. OP
    OP
    ibo man

    ibo man Senior Member
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    DATMATT,
    Thank you very much for clearifying that for me.:)
     
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