Question

In: Chemistry

51.       For a cell based on each of the following reactions run at standard conditions, calculate...

51.       For a cell based on each of the following reactions run at standard conditions, calculate the emf of the cell, the standard free energy change of the reaction, and the equilibrium constant of the reaction: Get the Potentials from the table of standard reduction potentials available on Blackboard)

            a)         Mn(s) + Cd +2 (aq) ------> Mn+2 (aq) + Cd(s)

            c)         2 Br - (aq) + I2 (s) --------> Br2 (l) + 2 I - (aq)

Solutions

Expert Solution

Equations:

EMF
cell = ERED + ECAT

Gibbs free energy:
deltaGº = -nFEºcell
n, number of transferred electrons.
F, Faraday constant. (96485.3329 s.A/mol)
cell, standard cell potential.

Nernst equation:
Ecell = Eºcell – (RT/nF)Ln(Q)
Ecell, cell potential.
cell, standard cell potential.
R, gas constant (8.314 J/K.mol)
T, temperature (K).
n, number of transferred electrons.
F, Faraday constant. (96485.3329 s.A/mol)

At equilibrium:
Ecell = 0
Q = K (equilibrium constant)

Clear K:
K = e(Eºcell.n.F/R.T)

_______________

a)
Mn --> Mn2+ + 2e-
Mn = 1.18 V

Cd2+ + 2e- --> Cd
Cd = -0.403 V

Standard EMF:
cell = 1.18 V - 0.403 V
cell = 0.777 V

Standard Gibbs free energy:
n = 2
Use Gibbs free energy equation.
deltaGº = -149938.2 J/mol

Equilibrium constant:
n = 2
T = 298 K (standard temperature)
Use Nernst equation at equilibrium.
K = 1.9174x1026

_______________

b)
2Br- --> 2Br + 2e-
Br = -1.066 V

I2 + 2e- --> 2I-
I = 0.535 V

Standard EMF:
cell = 0.535 V - 1.066 V
cell = -0.531 V

Standard Gibbs free energy:
n = 2
Use Gibbs free energy equation.
deltaGº = 102467.4 J/mol

Equilibrium constant:
n = 2
T = 298 K (standard temperature)
Use Nernst equation at equilibrium.
K = 1.0926x10-18


Related Solutions

Calculate E∘ for each of the following reactions, and tell which are spontaneous under standard-state conditions....
Calculate E∘ for each of the following reactions, and tell which are spontaneous under standard-state conditions. Part A 2Fe2+(aq)+Pb2+(aq)→2Fe3+(aq)+Pb(s) Express your answer using two decimal places. E∘ = V SubmitMy AnswersGive Up Part B Mg(s)+Ni2+(aq)→Mg2+(aq)+Ni(s) Express your answer using two decimal places. E∘ = V SubmitMy AnswersGive Up Part C Tell which are spontaneous under standard-state conditions. Check all that apply. Check all that apply. 2Fe2+(aq)+Pb2+(aq)→2Fe3+(aq)+Pb(s) Mg(s)+Ni2+(aq)→Mg2+(aq)+Ni(s)
Write the cell reaction and electrode half-reactions and calculate the standard potential of each of the...
Write the cell reaction and electrode half-reactions and calculate the standard potential of each of the following cells: a) Zn/ZnSO4(aq)//AgNO3(aq)/Ag b) Pt/K3[Fe(CN)6](aq), K4[Fe(CN)6](aq)//CrCl3 (aq)/Cr Please show all steps and clear writing. Thanks
Use the following half-reactions to write three spontaneous reactions, and calculate E cell for each reaction:...
Use the following half-reactions to write three spontaneous reactions, and calculate E cell for each reaction: a. Au+ (aq) + e- ----> Au (s) E= 1.69 V b. N2O (g) + 2H+ (aq) + 2 e- ----> N2 (g) + H2O (l) E= 1.77 V c. Cr3+ (aq) + 3e- ---> Cr (s) E= -0.74 V
Consider a galvanic cell based on the following line notation at standard conditions and 298K: Sn...
Consider a galvanic cell based on the following line notation at standard conditions and 298K: Sn | Sn2+ || Fe3+ | Fe Which of the following changes WILL NOT change the potential of the cell? Add equal amounts of water to each half cell Replace the Fe electrode with a Pt electrode Increase the concentration of Sn2+ Decrease the concentration of Fe3+ Replace the Sn electrode with a Pt electrod
A voltaic cell is assembled under standard conditions based on the following reaction : Ni(s) +...
A voltaic cell is assembled under standard conditions based on the following reaction : Ni(s) + 2 Ag+(aq) → Ni+2(aq) + 2 Ag(s) Indicate which statements, if any, about this voltaic cell are true by checking the box in front of each true statment. - The voltaic cell will always produce a positive potential. If the [Ni2+] is doubled while [Ag+] remains standard, the intial potential produced by the voltaic cell will double. If the [Ag+] is doubled while [Ni+2]...
Calculate the cell potential for a reaction in a electrolytic cell with the following half-reactions if:...
Calculate the cell potential for a reaction in a electrolytic cell with the following half-reactions if: [U 3+] = 0.10 M, [MnO4 - ] = 0.20M, [Mn2+], and [H+ ] = 0.20 M U 3+ + 3e -> U o Ecell = - 1.642 V MnO4 - + 8H+ + 5e- -> Mn2+ + 4H2O Ecell = +1.51 V
Use the standard reduction potentials to calculate the equilibrium constant for each of the following reactions:...
Use the standard reduction potentials to calculate the equilibrium constant for each of the following reactions: Note if deltaG° for each reaction would be greater than or less than zero. Co2+(aq) + Sn(s) = Co(s) + Sn2+(aq) Ag+(aq) + Cr2+(aq) = Ag(s) + Cr3+(aq)
Calculate the membrane potential of a neuron at standard temperature under each of the following conditions:...
Calculate the membrane potential of a neuron at standard temperature under each of the following conditions: a. The concentration of sodium, potassium and chloride is the same on both the inside and the outside of the membrane. b. The concentration of ions inside and outside the cell are as given below, but the relative permeability is the same for the three ions. c. The concentration of ions inside and outside the cell are as given below, but the relative permeability...
Calculate the concentration of 1,3-bisphophoglycerate under standard biochemical conditions if the cell is at equilibrium and...
Calculate the concentration of 1,3-bisphophoglycerate under standard biochemical conditions if the cell is at equilibrium and using the concentrations of [ATP]=4.42mM, ADP=332µM, and [3-phosphoglycerate] =23µM.
Based on the following cells, determine the (i) cell reaction, (ii) electrode half-reactions and (iii) standard potential.
Based on the following cells, determine the (i) cell reaction, (ii) electrode half-reactionsand (iii) standard potential. Then, based on the standard potential, determine if the cellcan be used as spontaneous voltaic cell or nonspontaneous electrolytic cell. (a) Pt|Ti3+(aq), Ti2+(aq)||Sn4+(aq), Sn2+(aq)|Pt(b) Mg|Mg2+(aq)||Mn2+(aq), H+ (aq)|MnO2(s)|Pt(c) Pt|F2(g)|HF(aq)||K2CrO4(aq)|Ag2CrO4(s)|Ag  
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT