The document describes a chemical reaction between copper sulfide (CuS) and nitric acid (HNO3) that produces copper nitrate (Cu(NO3)2), nitrogen monoxide (NO), sulfur (S), and water (H2O). It provides the balanced chemical equation and explains that sulfur is oxidized while nitrogen is reduced in the reaction. Finally, it scales up the balanced reaction to show the products when 3 moles of CuS reacts with 8 moles of HNO3.