Percent Composition

It is a percentage that you can calculate the mass of one of the elements in a chemical formula.

The Questions of the Fives:

1. If a compund contains 394.0g of Au, 96.3g of S and 192.0g of O, calculate the total malar mass and % compostion.

2. What percent of Rutin, which is found in buckwheat and in the fruit of the Fava D'anta tree etc, is C₂₇H₃₀O_x , has a total molar mass of 610g/mol. Find the number of oxygens there are in this compound and the percentage composition.

3. Calculate the percentage of the bold species in each of the following:
       a) CaCl2 + 2H2O

4. If a compund contains 394.0g of Au, 96.3g of S and 192.0g of O, calculate the total malar mass and % compostion.

5. What percent of Rutin, which is found in buckwheat and in the fruit of the Fava D'anta tree etc, is C₂₇H₃₀O_x , has a total molar mass of 610g/mol. Find the number of oxygens there are in this compound and the percentage composition.

5.Determine if the percent compostion of ammonium oxalate (NH4)2C2O4) is accurate
%N=22.6%
%H=6.5%
%C=19.4%
%O=51.6%

Solutions:

3. Total MM= 682.3g/mol

     % of Au= (394.0g/mol)/(682.3g/mol)=57.74%

     % of S= (96.3g/mol)/(682.3g/mol)=14.1%

     % of O=(192.0g/mol)/(682.3g/mol)=28.14%

4. MM oxygen= 610.0-324.0-30.0=256.0g/mol

          (256.0g/mol)/16=16 oxygen atoms

     % of C27=(324.0g/mol)/(610.0g/mol)=52.11%

     % of H=(30.0g/mol)/(610.0g/mol)=4.92%

     % of O=(256.0g/mol)/(610.0g/mol)=41.97%

5.MM ammonuium oxalate=124g/mol
% of N: 28.0g per mol/ 124g/mol x 100= 22.6%
% of H: 8.0 g per mol / 124g/mol x 100 = 6.5%
% of C: 24,0g per mol / 124g/mol x 100 = 19.4%
% of O: 24.0g per mol/ 124g/mol x 100= 51.6%
Thus the Percent Compostion is correct!!