A student made measurements on some electrochemical cells and calculated three quantities: • The standard reaction free energy AG°. The equilibrium constant K at 25.0 °C. • The cell potential under standard conditions E°. His results are listed below. Unfortunately, the student may have made some mistakes. Examine his results carefully and tick the box next to the incorrect quantity in each row, if any. Note: If there is a mistake in a row, only one of the three quantities listed is wrong. Also, you may assume the number of significant digits in each quantity is correct. Also note: for each cell, the number n of electrons transferred per redox reaction is 2. calculated quantities (Check the box next to any that are wrong.) cell K E A 2 226. kJ/ mol 39 3.92 x 10 1.17 V В 120. kJ/mol 1.05 x 10 -0.62 V 37 – 214. kJ/mol 3.10 x 10 -1.11 V

Write the cell notation for an electrochemical cell consisting of an anode where Sn (s) is oxidized to Sn2+ (aq) and a cathode where H+ (aq) is reduced to H2 (g) at a platinum electrode . Assume all aqueous solutions have a concentration of 1 mol/L and gases have a pressure of 1 bar.

A student made measurements on some electrochemical cells and calculated three quantities: • The standard reaction free energy AG. • The equilibrium constant K at 25.0 °C. • The cell potential under standard conditions E°. His results are listed below. Unfortunately, the student may have made some mistakes. Examine his results carefully and tick the box next to the incorrect quantity in each row, if any. Note: If there is a mistake in a row, only one of the three quantities listed is wrong. Also, you may assume the number of significant digits in each quantity is correct. Also note: for each cell, the number n of electrons transferred per redox reaction is 1. calculated quantities (Check the box next to any that are wrong.) cell n AGº K A 1 -19. kJ/mol 4.69 × 10 0 E 0.20 V 13 B 1 77. kJ/mol 3.09 × 10 0.80 V -14 C 1 75. kJ/mol 7.25 X 10 0.78 V

The Nernst equation is one of the most important equations in electrochemistry. To calculate the cell potential at non-standard-state conditions, the equation is E = E-2.303RTn Flog 10Q where E is the potential in volts, Eo is the standard potential in volts, R is the gas constant, T is the temperature in kelvins, n is the number of moles of electrons transferred, F is the Faraday constant, and Q is the reaction quotient. Using the common reference temperature, 25 °C or 298 K, the equation has the form E = E-(0.0592n)logQ The reaction quotient has the usual form Q = [products]x[ reactants]y A table of standard reduction potentials gives the voltage at standard conditions, 1.00 M for all solutions and 1.00 atm for all gases. The Nernst equation allows for the calculation of the cell potential E at other conditions of concentration and pressure. Part A For the reaction 2C03 + (aq) + 2CI-(aq)-> 2Co2 + (aq )+ Cl2(g). E = 0.483 V what is the cell potential at 25° C if the concentrations are…