Chemistry Percent Composition of Compounds?

I have missed a day in my chemistry class and am completely behind on how to find the percent composition of compounds. Can someone please help me determine the percent composition (of each element) for these compounds:

AlF3 Fe(HCO3)2 Fe3O4

It'd be great if you could explain how you did at least one of them. I'm sure I'm missing a really small point!

2 Answers

Relevance
  • david
    Lv 7
    4 weeks ago

    Fe(HCO3)2   ...  begin by finding the molar mass.

      1 Fe  ===  1(55.85)  =  55.85

      2 H  ===  2(1.00)  =  2.00

      2 C  ===  2(12.0)  =  24.0

      6 O  ===  6(16.0)  =  96.0

    ======================

      molar mass =   - - - -   177.85

      % Fe  =  55.85/177.85  X 100% =

      % H  =  2.00/177.85 X 100%  =

      % C  =  24.0/177.85 X 100%  =  

      % O  =  96.0/177.85 X 100%  =  

      ....  use your calculator ,, yu can do the rest

  • Fern
    Lv 7
    4 weeks ago

    AlF3: sum up atomic weights (I rounded to the nearest whole number)

    1Al + 3F = 1(27) + 3(19) = 27 + 57 = 84

    Percent Al = 27/84 *100= 32%Al

    Percent F = 57/84 *100 = 68%

    Fe(HCO3)2 ;

    1Fe + 2H + 2C + 6O

    1(56) + 2(1) + 2(12) + 6(16) = 178

    Percent Fe = 56/178 *100 = 31.5%

    Percent H = 2/178 * 100 = 1%

    Percent C = 24/178 *100 = 13.5%

    Percent O = 96/178 * 100 = 54%

Still have questions? Get your answers by asking now.