Reaction relevance

PHYSIC Our experiment consists in making a reaction between copper and silver nitrate. We will show, observe and explain you the result we will obtain. As I said, the reactants are copper (Cu) and silver nitrate (Ag+ + NO3-) which is composed of silver ions (Ag-) and nitrate ions (NO3-). In order to do this experiment, we have to use some glassware: a funnel (Entonnoir), a test-tube, a beaker, a teat-pipette and a filter. Before begin, we have to wear some required protection to avoid any kind of issues: There are gloves, goggles and a blouse of course because silver nitrate is irritant for the eyes and the skin. First, we put in the test tube the solution of silver nitrate thanks to the funnel. Then we add the wire of copper. The whole process may be quite long but we can already observe that residues are formed around the wire and fall in the bottom. We can conclude that the copper disappear step by step. We will call this solution S0 ("S zero") to be clearer. Our hypothesis is that the residues are the result of the transformation of silver ions to silver. At the same time, the disappearance of the wire might be due to the transformation of copper to copper ions. In order to prove this last hypothesis (If there are copper ions), we need to use a solution of sodium hydroxide (Na+ + OH-). So we filter and put S0 in a beaker. We have to be careful that none residue fall in the beaker, because it could alter the result. After that, we add the sodium hydroxide with a teat pipette. Right away, the solution becomes green/blue, that prove the presence of copper ions in S0. We admit that the nitrate ions (NO3-) are spectator ions, so obviously the solid formed is silver. Our hypothesis is now checked. BALANCE THE EQUATION: The products of the main reaction are silver and copper ions. Now, we're going to explain the test reaction: We put a solution of sodium hydroxide with S0, but remember we filter S0! Again, we admit that sodium ions are spectator ions. That gives us this EQUATION: