Will the total mass of the copper wire and silver nitrate be retained after a reaction? Why?
Yes, because neither matter nor energy can be created nor destroyed. This reaction does not generate gas, so the weight will remain the same. In all chemical reactions, the mass of the reactants is always exactly equal to the weight of the products. This was discovered by a French chemist by the name of Lavoisier. It was the beginning of real chemistry and the end of alchemy. Mass can change in a physical reaction. The mass of the products of nucleur fission or fusion are less than the starting material. This is because some of the mass has been changed into energy. However, the universe has all the mass and energy it began with and this will always remain the same forever.
