Mrs. Nielsen Name ___________________________________ Date ________________ Period _____ AP Chemistry Redox Practice Questions 1. Examine the five reactions shown below and identify those that can be classified as oxidation-reduction: a. 2H3PO4 + 3Ca(OH)2 —> Ca3(PO4)2 + 6H2O b. 2Cr + 3Cl2 —> 2CrCl3 c. C6H12O6 + 6O2 —> 6CO2 + 6H2O d. Na2CO3 —> Na2O + CO2 e. 2VO2+ + Zn + 4H+ —> 2V3+ + Zn2+ + 2H2O 2. The decomposition of a compound into simpler substances by means of an electrical current is called electrolysis. a. Write the balanced chemical equation for the electrolytic decomposition of water to its elements. b. Balance the following oxidation and reduction half-reactions for the decomposition of water. ___ H2O —> ___ O2 + ___ H+ + ___ e___ H2O + ___ e- —> ___ H2 + ___ OHc. Explain how the oxidation and reduction half-reactions may be combined to give the balanced chemical equation for the decomposition of water. What happens to the electrons and to the H+ and OH- ions? Mrs. Nielsen AP Chemistry 3. The usefulness of metals in structural applications depends on their physical and chemical properties. Corrosion is the oxidation of metals and is a common failing point for a metal structure. The table below represents observations above for the metals Cu, Mg, and Zn in various salt solutions. a. Identify the metal that is most susceptible to oxidation (corrosion). b. Identify the metal that is most resistant to oxidation. c. Because the silver metal is expensive, it was not used in the test shown above. Based on the reactions of Cu, Mg, and Zn with silver nitrate, explain why it was not necessary to test silver metal to deduce its reactivity. 4. Use a table of Standard Electrode Potentials to calculate ΔG° for this reaction: 2 Na(s) + 2 H2O(l) H2(g) + 2 OH- (aq) + 2 Na+(aq) Is the reaction spontaneous?