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chemical equation trouble

  • 20-11-2011 8:35pm
    #1
    ForzaKid
    Registered Users, Registered Users 2 Posts: 320 ✭✭


    Hi folks,Can somebody help me out ? I have a small idea how to do them but need extra help!..

    Determine the empirical formulas of the compounds with the following compositions by mass.



    10.4%C 27.8% S 61.7% Cl.. Express your answer as a chemical formula.


Comments

  • #2
    krd
    Banned (with Prison Access) Posts: 3,455 ✭✭✭krd


    ForzaKid wrote: »
    Hi folks,Can somebody help me out ? I have a small idea how to do them but need extra help!..

    Determine the empirical formulas of the compounds with the following compositions by mass.

    10.4%C 27.8% S 61.7% Cl.. Express your answer as a chemical formula.

    I gave it a crack - I haven't done one in a very very long time.

    This way.
    http://chemistry.about.com/od/workedchemistryproblems/a/empirical.htm

    1. Assume you have 1000 g of the substance (makes the math easier because everything is a straight percent).

    This means you have 104gC + 278gS + 617g Cl

    2. Convert the grams to moles for each element.
    Use this Periodic table - it gives the moles for each element.
    http://en.wikipedia.org/wiki/Periodic_table_(large_version)

    3. Find the smallest whole number ratio of moles for each element.

    104g C x (1 mol C)/(12.011g) = 8.6587 mol C
    278g S x (1 mol S)/(32.066 g) = 8.6696 mol S
    617g Cl x (1 mol Cl)/(35.453 g) = 17.4033 mol Cl

    8.6587 mol C/8.6587 = 1 mol C
    8.6696 mol S/8.6587 = 1.001 mol S
    17.4033mol Cl/8.6587 = 2.001 mol Cl

    A little more rounding

    8.6587 mol C/8.6587 = 1 mol C
    8.6696 mol S/8.6587 = 1 mol S
    17.4033mol Cl/8.6587 = 2 mol Cl

    the ratio is 1:1:2

    CCl2S - order using the Hill system

    And Viola h:170

    There's your chemical. chloromethanecarbothioyl chloride

    BEWARE - I could still be wrong. I'm just busking it. I can't remember how to check if the atoms would bind like that.


    If I'm right, I have to say, you kids have it so easy these days. When I was at school, I had a bad tempered alcoholic for a chemistry teacher, and a falling to pieces chemistry book as my only source of information.


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