science text unit idfk anymore😊
Copper (Cu) reacts with sulfur (S) to form copper sulfide as shown in the equation. A scientist adds 12.7 grams of Cu to 3.2 grams of S to start the reaction. In this reaction, all of the copper and all of the sulfur react. Before running the experiment, the scientist expected the products of the reaction will be total of 15.9 grams of copper sulfide (Cu2S). In 1-2 sentences, explain the law that the scientists used to predict that the product of the reaction would be15.9 grams of copper sulfide.