Acompound in a copper ore has the following percentage composition by mass:
55.6% copper, 16.4% iron, 28.0% sulfur.
calculate the empirical formula of the compound.
relative atomic masses (ar): s = 32; fe = 56; cu = 63.5
you must show all of your working.

show all working, x

1) since we are given percentages, we can assume we have 100 grams of the molecule.

55.6 % Cu ----> 55.6 grams Cu
16.4 % Fe------> 16.4 grams Fe
28.0% S--------> 28.0 grams S

2) convert each gram to moles using the molar masses given





3) we divide the smallest value of moles (0.293) to each one.

Cu --> 0.876 / 0.293= 3
Fe---> 0.293 / 0.293= 1
S-----> 0.875 / 0.293= 3

4) let's write the empirical formula

Cu₃FeS₃