CHEM 1212, UNIT4worksheet5 Questions And Correct Answers |100% Verified |Guaranteed Success | update- Kennesaw State University

1. Use the standard half-cell potentials listed below to calculate the standard cell potential for the following reaction occurring in an electrochemical cell at 25°C. (The equation is balanced.) 3 Cl2(g) + 2 Fe(s) → 6 Cl⁻(aq) + 2 Fe3+(aq) Cl2(g) + 2 e⁻ → 2 Cl⁻(aq) E° = +1.36 V Fe3+(aq) + 3 e⁻ → Fe(s) E° = -0.04 V Fe3+(aq) + 3 e⁻ E° = 0.04 V E°=(1.36 V)+(0.04 V) 1.40 V Fe(s) → 2. Identify the characteristics of a spontaneous reaction. A) ΔG° 0 B) ΔE°cell 0 C) K 1 D) all of the above 1 E) none of the above Chem 1212 UNIT 4 Worksheet 5 3. Which of the following reactions would be the most spontaneous at 298 K? A) A + 2 B → C; E°cell = +0.98 V B) A + B → 2 C; E°cell = -0.030 V C) A + B → 3 C; E°cell = +0.15 V D) A + B → C; E°cell = +1.22 V 4. a. What is the reduction half-reaction for the following overall galvanic cell reaction? Co2+(aq) + 2 Ag(s) → Co(s) + 2 Ag+(aq) Ag+(aq) + e⁻ → Ag(s) b. Does the reduction occur at the anode or the cathode? Cathode 5. Using the following standard reduction potentials, Fe3+(aq) + e- →Fe2+(aq) E° = +0.77 V Ni2+(aq) + 2 e- →Ni(s) E° = 0.23 V calculate the standard cell potential for the galvanic cell reaction given below, and determine whether or not this reaction is spontaneous under standard conditions. Ni2+(aq) + 2 Fe2+(aq) → 2 Fe3+(aq) + Ni(s) Anode: Fe2+(aq) → Fe3+(aq) + e- V E° anode= -0.77 (-0.23 V)+(-0.77 V)=-1 V Cathode: Ni2+(aq) +2 e- → Ni(s) 0.23 V E° cathode = 2 Not Spontaneous Chem 1212 UNIT 4 Worksheet 5 1. a. How many moles of electrons are being transferred in the following reaction? Sn(s) + 2 Cu2+(aq) cell  Sn2+(aq) + 2 Cu+(aq) Eo = +0.291 V Reduction half: Sn2+(aq)+ 2 e-  Sn(s) Oxidation half: 2 Cu2+(aq) 2 Cu2+(aq)+ 2 e-2 moles of electrons b. What is the standard free energy change and the equilibrium constant for the following reaction at 25 °C? ΔGo=-(2 mol)(96485 c/mol)(.291 V)= -56.2 kJ Ln k=(-56165.37 J)/(8.314 J/mol * 298.15 K)= 6.94*10^9 2. Consider a voltaic cell prepared using a Cr electrode in solution of Cr3+ and a Ag electrode in solution of Ag+. Ag+ + e- Cr3+ + 3 e-  Ag Eo = +0.800 V  Cr Eo = -0.74 V a. Calculate the standard cell potential. (.0800 V)-(-.74 V) = 1.54 V 3 Chem 1212 UNIT 4 Worksheet 5 b. Calculate the value of ΔGo for this cell. ΔGo = (3 mol)(96485 C/mol)(1.54 V) ΔGo = -445585.8 J ΔGo = -445.6 kJ