- 14 19 (a) Write the half reactions for a H - O fuel cell. 2 2 Find the theoretical cell voltage at 25°C if PH. = 1.0 ar P b 0.2 = and [H] = 0.5M at both b electrodes. (Real fuel cells operate at temperatures of 60° 1000°C and produce -0.7V.) (b) If the cell is 70% efficient at converting chemical energy into electrical energy, and a stack of cells produces 20 kW at 220 V, how many grams of H, are consumed in an hour? 2 (c) In the US, engines are frequently rated in "horsepower." Use Table 1-4 to convert 20 kW to horsepower. Answer (a) 1.219 V (b) 4.88 h (c) 26.8 horsepower 20. (a) 1.219 V (b) 4.88 g/h (c) 26.8 horsepower

- 14 19 (a) Write the half reactions for a H - O fuel cell. 2 2 Find the theoretical cell voltage at 25°C if PH. = 1.0 ar P b 0.2 = and [H] = 0.5M at both b electrodes. (Real fuel cells operate at temperatures of 60° 1000°C and produce -0.7V.) (b) If the cell is 70% efficient at converting chemical energy into electrical energy, and a stack of cells produces 20 kW at 220 V, how many grams of H, are consumed in an hour? 2 (c) In the US, engines are frequently rated in "horsepower." Use Table 1-4 to convert 20 kW to horsepower. Answer (a) 1.219 V (b) 4.88 h (c) 26.8 horsepower 20. (a) 1.219 V (b) 4.88 g/h (c) 26.8 horsepower

Chemistry: Principles and Reactions

8th Edition

ISBN:9781305079373

Author:William L. Masterton, Cecile N. Hurley

Publisher:William L. Masterton, Cecile N. Hurley

Chapter17: Electrochemistry

Section: Chapter Questions

Problem 105QAP: Consider a voltaic cell in which the following reaction occurs. Zn(s)+Sn2+(aq)Zn2+(aq)+Sn(s) (a)...

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Halide ions can he deposited at a silver anode, the reaction being Ag(s) + X- AgX(s) +e- Suppose that a cell was formed by immersing a silver anode in an analyte solution that was 0.0250 M Cl-,Br-, and I -ions and connecting the half-cell to a saturated calomel cathode via a salt bridge. (a) Which halide would form first and at what potential? Is the cell galvanic or electrolytic? (b) Could I- and Br- be separated quantitatively? (Take 1.00 l0-5 M as the criterion for quantitative removal of an ion.) If a separation is feasible, what range of cell potential could he used? (c) Repeat part (b) for I- and Cl-. (d) Repeat part (b) for Br- and Cl-.
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