1. Electrolytic Cells

2. An electrolytic cell is an electrochemical cell that undergoes a redox reaction when electrical energy is applied. It is most often used to decompose chemical compounds, in a process called electrolysis--the Greek word lysis means to break up. When electrical energy is added to the system, the chemical energy is increased. Electrolytic cells can consist of two half cells, or a single cell.

3. Non-Spontaneous Reactions In voltaic cells, electrons flow from the active metal to the ion of a less active metal spontaneously. In electrolytic cell, the battery can “pull” electrons from less active metals and reduce the ions of very active metals. Electrolysis led to the discovery of Group 1 and 2 elements, which can’t spontaneously re- acquire their valence electrons!

4. Which procedure requires the use of an external electric current to force a redox reaction to occur? polymerization distillation electrolysis saponification

5. Which energy transformation occurs when an electrolytic cell is in operation? chemical energy → electrical energy electrical energy → chemical energy light energy → heat energy light energy → chemical energy

6. An electrolytic cell has three component parts: an electrolyte and two electrodes (a cathode and an anode). The electrolyte is usually a solution of water or other solvents in which ions are dissolved. Molten salts such as sodium chloride are also electrolytes.

7. Which statement best describes the reaction represented by the equation below? 2NaCl + 2H 2 O + electricity → Cl 2 + H 2 + 2NaOH The reaction occurs in a voltaic cell and releases energy. The reaction occurs in a voltaic cell and absorbs energy. The reaction occurs in an electrolytic cell and releases energy. The reaction occurs in an electrolytic cell and absorbs energy.

8. Molten salts such as sodium chloride are also electrolytes. Remember, ionic compounds conduct electricity in the liquid state, but not as solids! Molten salts are also called “fused” salts.

9. The type of reaction in a voltaic cell is best described as a spontaneous oxidation reaction, only nonspontaneous oxidation reaction, only spontaneous oxidation-reduction reaction nonspontaneous oxidation-reduction reaction

10. Base your answer to the question on the information and diagram. The apparatus shown in the diagram consists of two inert platinum electrodes immersed in water. A small amount of an electrolyte, H 2 SO 4, must be added to the water for the reaction to take place. The electrodes are connected to a source that supplies electricity. What type of electrochemical cell is shown? oxidation cell electrolytic cell reduction cell voltaic cell

11. Hydrolysis of Water 2H 2 O (l)  H 2 (g) + O 2 (g) is non-spontaneous… Using a power source, water can be split into hydrogen and oxygen; A Hoffman Apparatus is essential for submarines, spaceships.

12. Oxidation always occurs at the anode. In an electrochemical cell, the anode is (-) In a electolytic cell, the anode is (+) Reduction always occurs at the cathode. In voltaic cells, the cathode is (+) In electrolytic cells, the cathode is (-)

13. Which type of cell does the diagram represent? electrolytic, with the anode at A electrolytic, with the cathode at A voltaic, with the anode at A voltaic, with the cathode at A

14. Electroplating Electroplating is used to change the surface properties of a substance. Corrosion resistance is a major feature made possible by electroplating Less active metals are plated onto a more active metal

15. Electroplating The anode (the less active metal) is oxidized by the power source. The electrons reduce copper ions in the solution, which coat the cathode. The anode replenishes the electrolyte as it decomposes.

16. The diagram represents the electroplating of a metal fork with Ag(s). Which part of the electroplating is represented by the fork? the anode, which is the negative electrode the cathode, which is the negative electrode the anode, which is the positive electrode the cathode, which is the positive electrode

17. Which equation represents the half-reaction that takes place at the fork? Ag + + NO 3 − → AgNO 3 AgNO 3 → Ag + + NO 3 − Ag + + e − → Ag(s) Ag(s) → Ag + + e −