Which process represents a chemical change? (1) melting of ice(2) corrosion of copper(3) evaporation of water(4) crystallization of sugar

             Corrosion of Copper is a chemical change.

                   Copper like Iron when come in contact with moisture and oxygen oxidized and corrodes according to following equation,

                                             4 Cu  +  O₂    →   2 Cu₂O

This corrosion results in lost of conductivity, strength and luster of copper. As in this reaction two substances i.e Cu and O₂ are reacting to produce a completely new substance i.e. Cu₂O hence, it is declared as chemical change.