What Is The Mass Percent?

A sample weighing 14.98g and containing a small amount of copper was treated to give a solution containing aqueous Cu^2+ ions.  Sodium iodide was then added ti yield solid copper (I) iodide plus I3^- ion, and the I3^- was titrated with thiosulfate, S2O3^2-.  The titration required 10.49mL of .100M Na2S2O3 for complete reaction.  What is the mass percent copper in the sample?  The balanced equations are…

2Cu^2+(aq)+5I^-(aq)—->2CuI(s)+I3^-(aq)

I3^-(aq)+2S2O3^2-(aq)—->3I^-(aq)+S4O6^2-(aq)

Calculating Mass Percent

The metal content of iron in ores can be determined by a redox procedure in which the sample is first oxidized with Br2 to convert all the iron to Fe3+ and then titrated with Sn2+ to reduce the Fe3+ to Fe2+. The balanced equation is
2Fe3+(aq)+Sn2+(aq)→2Fe2+(aq)+Sn4+(aq)

What is the mass percent Fe in a 0.1900g sample if 12.50mL of a 0.1015 M Sn2+ solution is needed to titrate the Fe3+?