[livipivi88]

nitric acid is used to analyze sulfide ore

the two half reactions described by the problem are...

S2- > S  +  2e-
3e-  +  4H+  +  NO3- > NO  +  2H2O

the question wants to find the percent of sulfur in the ore if 64.5 ml of a .125M HNO3 solution is required to react exactly with a 1.00g sample of ore. i get how to do the math to find moles of sulfur, but WHEN I WANT TO FIND THE PERCENT, WHAT DO I PUT THE MOLES OF SULFUR OVER? WHAT IS SULFIDE ORE?

[mike]

It shouldn't matter what the ore is if you are doing weight percent, just convert moles of S into grams of S and work out as a percentage of 1.00g.