Question

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 (Cu2S). 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.

Answer 1

the equastion is this: 2Cu+S→Cu2S

Answer 2

The scientist used the law of conservation of mass, which states that matter cannot be created or destroyed, to predict that the product of the reaction would be 15.9 grams of copper sulfide, since the total mass of the reactants (12.7 grams of Cu and 3.2 grams of S) is equal to the total mass of the product (15.9 grams of Cu2S).