Electrochemistry is the study of chemical processes that result in electron movement. Redox reactions are reactions which include changes to the oxidation states of elements. Oxidation is the process when a substance loses electrons, and reduction is the process when a substance gains electrons. The substance that is oxidized is referred to as the reducing agent, and the substance that is reduced is referred to as the oxidizing agent.
In order to bring about redox reactions in electrolytic cells, the use of an external source of electrical energy is necessary; otherwise, the reaction would be nonspontaneous. Electrolytic cells are composed of two half-cells and the direction of electron flow in electrolytic cells is from anode to cathode. During the process of electrolysis, an electric current passes through a solution of an ionic compound that is referred to as the electrolyte. Redox reactions, which occur at the electrodes, form electrically neutral products after removing the charges on the ions. Components of an Electrolytic Cell (Figure from Pearson IB HL Chemistry Textbook )
This investigation will include electrolysis using copper electrodes. Copper is widely regarded as an efficient electrical conductor. The net reaction of the electrolysis of copper will be the movement of Cu2+(aq) from where it is produced at the anode to the cathode where is it discharged as Cu(s). The observed changes at the electrodes are a pinkish brown color of Cu deposited on the cathode, disintegration of the Cu anode, no change in the pH of the solution, and no change in the intensity of the blue color of the solution because Cu2+ ions are both formed and removed from the solution so their concentration remains constant.
A result of the electrolysis of copper in a copper sulfate solution is that copper will be electroplated onto the cathode. Electroplating is the process of plating one metal onto another through electrolysis. Electroplating was first discovered in 1805 by Luigi Brugnatelli. In 1840, the Elkington cousins designed a feasible electroplating method for gold and silver that spread widely throughout the world. The first step in the process of electroplating is to deposit a negative charge onto a metal. After the metal contains a negative charge, that metal is then submerged into a solution of electrolytes which contain positively charged metal ions. After the metal is placed in the solution, the two metals are attracted to each other. Electroplating allows manufacturers to use inexpensive metals for the interiors of their products and then apply different metals on the exterior to prevent the corrosion of a metal. Electroplating is also used for decorative purposes within the jewelry and automobile industries.