The Nernst Equation The Nernst equation is one of the most important equations i

Question

The Nernst Equation 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 degree - 2.303 RT/nF log_10 Q where E is the potential in volts, E degree 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. At standard temperature, 25 degree C or 298 K, the equation has the form E = E degree - (0.0592/n) log ! 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. For the reaction 2Co^3+(aq) + 2Cl(aq) rightarrow 2Co^2+(aq) + Cl_2(g). E degree = 0.483 V what is the cell potential at 25 degree C if the concentrations are [Co^3+] = 0.830 M, [Co^2+] = 0.199 M, and [Cl^-] = 0.358 M and the pressure of Cl_2 is P_cl2 = 6.50 atm ?

Explanation / Answer

we can use the reduced equation at standard conditions which is:
E = Eº - 0.0592/n logQ

LEt's calculate Q first:

Q = [Cl2][Co2+] / [Cl-]2[Co3+]2

The concentration of Cl2 is calculated as:
C = P/RT = 6.50 / (0.0821*298) = 0.266 M

Q = (0.266)(0.199)2 / (0.83)2(0.358)2
Q = 0.1193

Now, let's calculate E (n=2)
E = 0.483 - 0.0592/2 log(0.1193)
E = 0.5103 V

Hope this helps

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.