when i add steel wool into the copper(II) sulfate pentahydrate solution, it turns into pinkish red and then break down into tiny particles (greyish colour) as i stir it. when the solution is pour down into a filter paper, the residue is believed to be copper and the solution that is filtered is iron sulfate.can anyone explain why the metal displacement take place??why the residue is copper and why iron sulfate is formed?
Iron goes into solution, and copper comes out. Assume that Fe is divalent, and the sulfate is not hydrated; the resulting equation is trivial to balance.
This was a single-replacement reaction. Iron is higher on the activity series of metals than copper. The iron ions went into solution and the copper ions ppt out of solution. As the Cu 2+ ions came out of solution the color of the solution changed from blue to reddish. You recover the solid Cu when you filter the material. The Fe atoms were oxidized and the Cu ions were reduced. 2 Fe + 3 CuSO4 --> Fe2(SO4)3 + 3 Cu
This process is called Copper Cementation. It was used to recover copper from leached ores until the mid 1950’s when solvent extraction technology was developed. Cementation is Spanish for precipitation and named for the use of the process, carried out on an industrial scale, in the copper mines in the Rio Tinto region of Spain in the mid 18th century. electrochem.cwru.edu/ed/encycl/ar... Cementation is the process of spontaneous reduction of the ions of a metal by another metal above it in the electromotive series. For example, a piece of iron immersed in copper sulfate solution will be immediately covered by a thin film of copper. The iron is being anodically dissolved while copper is electroplated on its surface cathodically. This process is also called metal displacement reaction or galvanic displacement. electrochem.cwru.edu/ed/dict.htm#... The copper in solution is, in effect, “traded” for iron by contacting the copper-bearing solution with elemental iron. Metallic copper precipitates on the iron surface while an electrochemical equivalent of iron goes into solution.
