make this into a paragraph that looks like a 8th grader did:
The scientist used the law of conservation of mass to predict that the product of the reaction would be 15.9 grams of copper sulfide. This law states that matter cannot be created or destroyed in a chemical reaction, so the total mass of the reactants must be equal to the total mass of the products.
The scientist used this thing called the law of conservation of mass. They said that this law can tell you what will happen in a chemical reaction. They predicted that if some reactants were mixed together, it would make about 15.9 grams of copper sulfide. The law says that you can't make or destroy matter during a chemical reaction. So, the total mass of what you start with (the reactants) has to be the same as the total mass of what you end up with (the products).
The scientist was like, "Let me use the law of conservation of mass to guess what will come out of the reaction." This law is all about how matter can't just disappear or appear during a chemical reaction. So, the total weight of the stuff we start with has to be the same as the total weight of the stuff we end with. In this case, the scientist figured that the reaction would make 15.9 grams of copper sulfide.
So, the scientist used this thing called the law of conservation of mass to figure out what would happen in this reaction. Basically, this law says that you can't make or get rid of any stuff during a chemical reaction. Everything that goes into the reaction needs to come out as something else. So, the scientist did some calculations and predicted that in this reaction, we would end up with 15.9 grams of copper sulfide as the final product. That means, after everything happens, we would have exactly that much copper sulfide. It's like a balancing act where the total mass of all the stuff we start with has to be equal to the total mass of all the stuff we end up with.
