Final answer:
An iron nail in copper sulfate solution undergoes a chemical change, where iron displaces copper from the solution, forming copper deposits on the nail and a colorless iron(II) sulfate solution.
Step-by-step explanation:
When an iron nail is placed in a solution of copper sulfate, after about an hour, one would expect to see the iron nail coated with a red-brown substance, which is elemental copper deposited on its surface. The blue color of the copper sulfate solution may also start to fade because iron ions replace the copper ions in the solution, forming a colorless or pale green iron(II) sulfate solution.
The changes observed are indeed chemical in nature. They result from a redox reaction where iron is oxidized to iron(II) ions (Fe2+), and copper(II) ions from the copper sulfate solution are reduced to copper metal (Cu).
The word equation for the chemical change is:
Iron (s) + Copper(II) sulfate (aq) → Copper (s) + Iron(II) sulfate (aq).