The Title should actually be "Gravimetric Analysis" srry about that but i cant change it now :( 1. A 6.34-g geological sample, containing the mineral Boulangerite (Pb5Sb4S11) as the only lead-bearing compound, is subjected to chemical treatment in which the lead is quantitatively recovered as solid PbCl2. The mass of PbCl2 obtained is 3.80 g. What was the percentage (by mass) of Pb5Sb4S11 in the sample? 2. n=m/MM %yield= (actual yield over theoretical yield) * 100 3. Well im guessing the equation is something like Pb5Sb4S11 -------> PbCl2(s) how to get cl in there or SbS out :S mass is given as 3.8g I have no clue can someone can get me started atleast?