SOLVED

51) A voltaic cell is constructed with two Zn2+-Zn electrodes, where the half-reaction is Zn2+ + 2e- → Zn(s)E° = -0.763 V The concentrations of zinc ion in the two compartments are 5.50 M and 1.95 × 10-2 M, respectively. The cell emf is ________ V. A) -2.71 × 10-3 B) -215 C) 0.0725 D) 0.145 E) -0.759 52) The standard emf for the cell using the overall cell reaction below is +2.20 V: 2Al(s) + 3I2(s) → 2AI3+(aq) + 6I-(aq) The emf generated by the cell when [AI3+] = 3.0 × 10-3 M and [I-] = 0.50 M is ________ V. A) 2.20 B) 2.27 C) 2.13 D) 2.34 E) 2.23 53) The standard emf for the cell using the overall cell reaction below is +0.48 V: Zn(s) + Ni2+(aq) → Zn2+(aq) + Ni(s) The emf generated by the cell when [Ni2+] = 0.100 M and [Zn2+] = 2.25 M is ________ V. A) 0.56 B) 0.50 C) 0.44 D) 0.40 E) 0.52 54) The electrolysis of molten AlCl3 for 2.50 hr with an electrical current of 15.0 A produces ________ g of aluminum metal. A) 113 B) 0.466 C) 3.50 × 10-3 D) 12.6 E) 37.8 55) For a galvanic cell that uses the following two half-reactions, Cr2O72-(aq) + 14 H+(aq) + 6 e- → 2 Cr3+(aq) + 7 H2O(l) Pb(s) → Pb2+(aq) + 2 e- how many moles of Pb(s) are oxidized by one mole of Cr2O72-? A) 1 B) 2 C) 3 D) 6 56) How many kilowatt-hours of electricity are used to produce 3.50 kg of magnesium in the electrolysis of molten MgCl2 with an applied emf of 4.50 V? A) 0.0288 B) 0.0347 C) 8.7 D) 34.7 E) 17.4 57) The most useful ore of aluminum is bauxite, in which Al is present as hydrated oxides, The number of kilowatt-hours of electricity required to produce of aluminum from electrolysis of compounds from bauxite is ________ when the applied emf is A) 0.0213 B) 0.0469 C) 31.3 D) 15.6 E) 46.9 58) How many seconds are required to produce 4.00 g of aluminum metal from the electrolysis of molten AlCl3 with an electrical current of 15.0 A? A) 21.6 B) 7.20 C) 9.53 × 102 D) 2.32 × 105 E) 2.86 × 103 59) How many grams of chromium metal are plated out when a constant current of 8.00 A is passed through an aqueous solution containing Cr3+ ions for 320. minutes? A) 27.6 g B) 49.2 g C) 82.4 g D) 248 g 60) How many grams of nickel metal are plated out when a constant current of 15.0 A is passed through aqueous NiCl2 for 40.0 minutes? A) 7.35 g B) 11.0 g C) 21.9 g D) 24.2 g 61) How long must a constant current of 50.0 A be passed through an electrolytic cell containing aqueous Cu2+ ions to produce 3.50 moles of copper metal? A) 0.267 hours B) 0.533 hours C) 1.88 hours D) 3.75 hours 62) The town of Natrium, West Virginia, derives its name from the sodium produced in the electrolysis of molten sodium chloride (NaCl) mined from ancient salt deposits. The number of kilowatt-hours of electricity required to produce 3.00 kg of metallic sodium from the electrolysis of molten NaCl(s) is ________ when the applied emf is 5.00 V. A) 17.5 B) 0.0572 C) 0.0175 D) 35.0 E) 8.7 63) The gas OF2 can be produced from the electrolysis of an aqueous solution of KF, as shown in the equation below. OF2(g) + 2 H+(aq) + 4 e- → H2O(l) + 2 F-(aq)E° = +2.15 V Using the given standard reduction potential, calculate the amount of OF2 that is produced, and the electrode at which the OF2 is produced, upon the passage of 0.0600 faradays through an aqueous KF solution. A) 0.810 g of OF2 at the anode. B) 3.25 g of OF2 at the anode. C) 0.810 g of OF2 at the cathode. D) 3.25 g of OF2 at the cathode.