Question

In: Chemistry

A voltaic cell is constructed that uses the following reaction and operates at 298 K. Zn(s)...

A voltaic cell is constructed that uses the following reaction and operates at 298 K. Zn(s) + Ni2+(aq) Zn2+(aq) + Ni(s) (a)

What is the emf of this cell under standard conditions?______ V

(b) What is the emf of this cell when [Ni2+] = 2.24 M and [Zn2+] = 0.112 M?_____ V

(c) What is the emf of the cell when [Ni2+] = 0.298 M and [Zn2+] = 0.925 M?____ V

Solutions

Expert Solution

Ni2+(aq) + 2 e --> Ni(s) here Eo = –0.257
Zn(s) --> Zn2+(aq) + 2 e here Eo = +0.763

so
Zn(s) + Ni2+(aq) → Zn2+(aq) + Ni(s)
has Eo = 0.506 volts & n = 2 moles of electrons

-----------------------------------------------------------------------------------

nernst equation is
E = Eo - (0.0592 /n) (log Q)
E = Eo - (0.0592 /n) (log Q)
E = 0.506 - (0.0592 / 2) (log [products] / reactants]
E = 0.506 - (0.0296) (log [Zn+2] / [Ni+2]

a) What is the emf of this cell when [Ni2+ ] = 2.24 M and [Zn2+ ] = 0.112 M?
E = 0.506 - (0.0296) (log [Zn+2] / [Ni+2]
E = 0.506 - (0.0296) (log [0.112]/ [2.24]
E = 0.506 - (0.0296) (log 0.047)
E = 0.506 - (0.0296) (-1.32)
E = 0.506+ 0.039
your first answer is
E = 0.545 volts
======================================...

(b) What is the emf of the cell when [Ni2+ ] = 0.298 M and [Zn2+ ] = 0.925M?
E = 0.506 - (0.0296) (log [Zn+2] / [Ni+2]
E = 0.506 - (0.0296) (log [0.925] / [0.298]
E = 0.506 - (0.0296) (log 3.10)
E = 0.506 - (0.0296) (0.491)
E = 0.506 - 0.014
your secoond answer is
E = 0.42 volts


Related Solutions

A voltaic cell is constructed that uses the following reaction and operates at 298 K: Zn(s)+Ni2+(aq)→Zn2+(aq)+Ni(s)....
A voltaic cell is constructed that uses the following reaction and operates at 298 K: Zn(s)+Ni2+(aq)→Zn2+(aq)+Ni(s). a. What is the emf of this cell when [Ni2+]= 2.10 M and [Zn2+]= 0.160 M ? b. What is the emf of the cell when [Ni2+]= 0.100 M and [Zn2+]= 0.860 M ? Thanks!
A voltaic cell utilizes the following reaction and operates at 298 K. 3 Ce4+(aq) + Cr(s)...
A voltaic cell utilizes the following reaction and operates at 298 K. 3 Ce4+(aq) + Cr(s) 3 Ce3+(aq) + Cr3+(aq) (a) What is the emf of this cell under standard conditions? V (b) What is the emf of this cell when [Ce4+] = 2.0 M, [Ce3+] = 0.014 M, and [Cr3+] = 0.011 M? V (c) What is the emf of the cell when [Ce4+] = 0.56 M, [Ce3+] = 0.82 M, and [Cr3+] = 1.3 M? V
1.) A voltaic cell utilizes the following reaction and operates at 298 K: 3Ce4+(aq)+Cr(s)→3Ce3+(aq)+Cr3+(aq). What is...
1.) A voltaic cell utilizes the following reaction and operates at 298 K: 3Ce4+(aq)+Cr(s)→3Ce3+(aq)+Cr3+(aq). What is the emf of the cell when [Ce4+]= 1.3×10−2 M ,[Ce3+]= 2.6 M , and [Cr3+]= 1.7 M ? 2.)Calculate the equilibrium constant K at 298 K: Aqueous iodide ion is oxidized to I2(s) by Hg22+(aq) In acidic solution, copper (I) ion is oxidized to copper (II) ion by nitrate ion In basic solution, Cr(OH)3(s) is oxidized to CrO2−4(aq) by ClO−(aq)
Calculate the cell potential and the equilibrium constant for the following reaction at 298 K: I2(s)...
Calculate the cell potential and the equilibrium constant for the following reaction at 298 K: I2(s) + Hg(l) = 2I-(aq) + Hg2+(aq) Hint: Carry at least 5 significant figures during intermediate calculations to avoid round off error when taking the antilogarithm. Equilibrium constant: -------
calculate E cell at 298 K (25 c) for Zn (s) + Cu 2+ (aq) -->...
calculate E cell at 298 K (25 c) for Zn (s) + Cu 2+ (aq) --> Zn 2+ (aq) + Cu (s) when [Zn 2+]=.0010 M and [Cu 2+]=.10 M
3) Consider a voltaic cell in which the following reaction occurs: Zn(s) + Sn2+(aq)  Zn2+(aq)...
3) Consider a voltaic cell in which the following reaction occurs: Zn(s) + Sn2+(aq)  Zn2+(aq) + Sn(s) a) Calculate Eo for the cell. b) when the cell operates, what happens to the concentration of Zn2+? The concentration of Sn2+ ? c) When the cell voltage drops to zero, what is the ratio of the concentration of Zn2+ to that of Sn2+ ? d) If the concentration of both cations is 1.0 M originally, what are the concentrations when the...
1. A voltaic cell is constructed that is based on the following reaction: Sn2+(aq)+Pb(s)→Sn(s)+Pb2+(aq). a. If...
1. A voltaic cell is constructed that is based on the following reaction: Sn2+(aq)+Pb(s)→Sn(s)+Pb2+(aq). a. If the concentration of Sn2+ in the cathode compartment is 1.50 M and the cell generates an emf of 0.22 V , what is the concentration of Pb2+ in the anode compartment? b. If the anode compartment contains [SO2−4]= 1.50 M in equilibrium with PbSO4(s), what is the Kspof PbSO4? 2. A voltaic cell is constructed with two silver-silver chloride electrodes, each of which is...
A voltaic cell is constructed that is based on the following reaction: Sn2+(aq)+Pb(s)→Sn(s)+Pb2+(aq). 1. If the...
A voltaic cell is constructed that is based on the following reaction: Sn2+(aq)+Pb(s)→Sn(s)+Pb2+(aq). 1. If the concentration of Sn2+ in the cathode compartment is 1.50 M and the cell generates an emf of 0.25 V , what is the concentration of Pb2+ in the anode compartment? 2.If the anode compartment contains [SO2−4]= 1.00 M in equilibrium with PbSO4(s), what is the Ksp of PbSO4?
A voltaic cell is constructed that is based on the following reaction: Sn2+(aq)+Pb(s)→Sn(s)+Pb2+(aq). Part A If...
A voltaic cell is constructed that is based on the following reaction: Sn2+(aq)+Pb(s)→Sn(s)+Pb2+(aq). Part A If the concentration of Sn2+ in the cathode compartment is 1.50 M and the cell generates an emf of 0.18 V , what is the concentration of Pb2+ in the anode compartment? Part B If the anode compartment contains [SO2−4]= 1.40 M in equilibrium with PbSO4(s), what is the Ksp of PbSO4?
23. A voltaic cell is constructed with Cr3+/Cr and Zn2+/Zn half-cells at 25 °C. a. If...
23. A voltaic cell is constructed with Cr3+/Cr and Zn2+/Zn half-cells at 25 °C. a. If the concentration of Zn2+ is 0.10 M, what concentration of Cr3+ should be used so that the overall cell potential is 0 V? b. What concentration of Cr3+ should you use to make the cell consume Zn (s)? c. What concentration of Cr3+ should you use to make the cell deposit Zn (s)?
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT