Question

Standard reduction potentials are listed for reactions under standard conditions. Standard conditions are 1 M concentrations of ions, 1 atm (or 1 bar) partial pressures for gases, and a temperature of 298 K a. In Part I, you were asked to compare your measured cell potential to a calculated standard cell 3. potential. The cell potential you measured was for a galvanic cell you prepared using 0.10 M solutions of Pb and Cu, not 1.0 M solutions. Write out the balanced equation for this cell, then give the Nernst equation for this cell. From the Nernst equation, explain why the cell potential under these nonstandard conditions should be equal to the standard cell potential for this particular reaction. Explain how the measured cell potential would differ from the calculated standard cell potential if the temperature in the lab was 20 °C when the experiment was done. b. (Hint: Look at the Nernst eq. given in (a).) 4. The corrosion of iron is an example of a galvanic cell. When iron rusts, a small electrochemical cell is formed in a water droplet, as seen in Figure 2 below. Water droglet Air Rust Dissolved O, oxidives Fe further to Fe befor it is deposited as rust (Fe O,-HO) o, Fe O, metal Anode region Fe +2 Electrons flow from anode to cathode through the metal, while ions flow through the water deoplet Copyright Fountainhead Pres Figure 2. A chemical mechanism describing rust formation. Part I Note color of leads required to get a positive voltage. er is hooked to the Liol color wire, and lead is hooked tothe Blaccolor woire to get color wire, and lead is hooked to the color wire to get positive cell potential measurement. Therefore, when a positive cell potential is measured, the metal ttached to the Ccolor wire undergoes oxidation, and the metal attached to the eocolor wire undergoes reduction. Measured cell potential: 4V 48t Average cell potential: 485 Calculated standard cell potential for this same reaction (show your work) 34 (13 0.47

Answer 1

Ansuer ° 3(a) SHandand poduction potentials ana Riste4 unclat standond conditionS is same as Tha standlord cel potential han Tha Contentration ob ions om because it ^o Sea So putting The values in bormula c l.e.,213 K 3b) JoJ The Yotio br concen trations ob- ions is - E.ceu - (3-3 tu ai«c1 x T4jod)log/ C, cei