Definitions
For each of the following balanced half-reactions, determine whether an oxidation or reduction is occurring.
Fe3+ + 3e‑ ⟶ Fe
Cr⟶Cr3+ + 3e‑
MnO42- ⟶MnO4- + e‑
Li+ + e‑ ⟶Li
Balancing with ½ reaction method
Given the following pairs of balanced half-reactions or unbalanced reactions, determine the balanced reaction for each pair of half-reactions in an acidic solution and in a basic solution. Identify the species that undergoes oxidation, the species that undergoes reduction, the oxidizing agent, and the reducing agent in each of the reactions below.
Ca⟶Ca2+ +2e e‑,F2+2 e‑ ⟶ 2F−
Fe2+ (aq) + MnO4-(aq) ⟶ Fe3+(aq) + Mn2+(aq)
Cu(s) + NO3-(aq) ⟶ Cu2+(aq) + NO2(g)
Ag⟶Ag++ e‑ , MnO4-+ 4H+ + 3 e‑ ⟶MnO2+2H2O
e. SO32-(aq) + Cu(OH)2(s)⟶SO42-(aq)+Cu(OH)
f. Al(s)+CrO42-(aq)⟶Al(OH)3(s)+Cr(OH)4-(aq)
Galvanic Cells and Spontaneity
Write the following balanced reactions using cell notation. Use platinum as an inert electrode, if needed.
Mg(s) + Ni2+(aq)⟶Mg2+(aq) + Ni(s)
2Ag+(q)+Cu(s)⟶Cu2+(aq) + 2Ag(s)
Mn(s)+Sn(NO3)2(aq)⟶Mn(NO3)2(aq) + Sns)
Given the following cell notations, determine the species oxidized, species reduced, and the oxidizing agent and reducing agent, without writing the balanced reactions.
Mg(s)│Mg2+(aq)║Cu2+(aq)│Cu(s)
Ni(s)│Ni2+(aq)║Ag+(aq)│Ag(s)
For each reaction listed, determine its standard cell potential at 25 °C and whether the reaction is spontaneous at standard conditions.
Mn(s) 7+ Ni2+(aq)⟶Mn2+(aq) + Ni(s)
3Cu2+(aq) + 2Al(s)⟶2Al3+(aq) + 2Cu(s)
Na(s) + LiNO3(aq)⟶NaNO3(aq) + Li(s)
Nernst Equation
For the standard cell potentials given here, determine the ΔG° for the cell in kJ.
0.000 V, n = 2
+0.434 V, n = 2
−2.439 V, n = 1
For the ΔG° values given here, determine the standard cell potential for the cell.
12 kJ/mol, n = 3
−45 kJ/mol, n = 1
For the following reaction at nonstandard conditions, is the process spontaneous?
Co(s)+Fe2+ (aq,1.94M)⟶Co2+ (aq, 0.15M)+Fe(s)
Is it spontaneous at the following conditions? [Fe2+] = 150.5M, [Co2+] = 0.00015M