Answer:
Le Chatelier's principle is an observation about chemical equilibria of reactions. It states that changes in the temperature, pressure, volume, or concentration of a system will result in predictable and opposing changes in the system in order to achieve a new equilibrium state.
For #4 first find the molar mass(M) of copper then use that and the mass (m) n=m/M to find moles(n) using moles and the volumes find the concentration using c=n/V
The answer is 60 minutes to complete 50% of reaction.