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 a total of 15.9 grams of copper sulfide (CuzS). In 1-2 sentences, explain the law that the scientist used to predict that the product of the reaction would be 15.9 grams of copper sulfide.

1 answer

The scientist used the Law of Conservation of Mass, which states that mass is neither created nor destroyed in a chemical reaction. Therefore, the total mass of the reactants (12.7 grams of Cu + 3.2 grams of S = 15.9 grams) should equal the mass of the products, leading to the prediction of 15.9 grams of copper sulfide (Cuâ‚‚S) as the product of the reaction.