Question

0.509g sample pure platinumetal was reacted with HCl to firm O.889g of platinum and chlorine. what is the percent by mass of platinum

Answer 1

Platinum plus chlorine equals 0.889 grams whereas the platinum alone is 0.509grams so 0.509/0.889grams = 57%  of the mass of the platinum plus chlorine. The chlorine would be 0.889-0.509=0.38 grams. The chlorine would make up about 42.7% of the total mass in grams.