Write down a half-reaction that explains the change that occurs on the surface of the copper spoon during electrolysis.
To write down the half-reaction explaining the change on the surface of a copper spoon during electrolysis, we need to understand the process and the species involved. Electrolysis involves the decomposition of a compound by passing an electric current through it. In this case, let's consider the electrolysis of a copper (II) sulfate solution (CuSO4) using copper spoon as the cathode, which is where reduction occurs.
The reduction half-reaction at the cathode is given by:
Cu^2+(aq) + 2e^- -> Cu(s)
In this reaction, Cu^2+ ions from the copper sulfate solution are reduced to metallic copper (Cu) when two electrons (2e^-) are gained at the cathode (the surface of the copper spoon). The copper ions in the solution gain electrons and are deposited onto the surface of the spoon, causing the spoon to become coated with a layer of copper.
To summarize, during electrolysis, at the cathode, the copper (II) ions in the solution gain electrons and reduce to copper metal, leading to a copper coating on the surface of the copper spoon. This is represented by the reduction half-reaction: Cu^2+(aq) + 2e^- -> Cu(s).