What is Nernst equation: Definition and 22 Discussions
In electrochemistry, the Nernst equation is an equation that relates the reduction potential of a reaction (half-cell or full cell reaction) to the standard electrode potential, temperature, and activities (often approximated by concentrations) of the chemical species undergoing reduction and oxidation. It was named after Walther Nernst, a German physical chemist who formulated the equation.
I'm working with the Nernst equation with pressure differences right now:
## E = E_t + \frac{RT}{nF}ln ((P/P_0)^{\Delta \eta_G})##
I'm assuming pure reactants here so, so I'm omitting the product terms: ##\frac{\Pi_{products} x_i ^{\nu_i}}{\Pi_{reactants} x_i ^{\nu_i}}## which would normally...
Ecell = E0cell - (RT/nF)lnQ
So I understand the Nernst Equation, but I don't have some info. (Please bare with me, I'm in secondary)
I'm doing a Cu - Al cell. My E cell is negative (-1.33). Does this have an affect on the equation?
What exactly does E0 stand for? I understand how to find E...
Homework Statement
The reduction of O2 to H2O in acidic solution has a standard reduction potential of +1.23 V. What is the effect on the half-cell potential at 25 °C when the pH of the solution is increased by one unit?
O2(g) + 4H+(aq) + 4e- –> 2 H2O(l)
(A) The half-cell potential...
Hello everyone,
I am not sure if this question is comfortable in the chemistry section but I will try my luck. I have been dealing with lambda sensors a little bit and when I look at the characteristic voltage lambda curve I keep asking myself why it flatens out when getting into the rich...
Homework Statement
Homework Equations
Nernst Equation where Q = [product]/[reactants], R = 8.314, F = 96500
The Attempt at a Solution
I got E° to be 0.012 V because E° of cathode - E° of anode. -0.131 - (-0.143) = 0.012.
The balanced equation I got was: Pb2+ + Sn → Pb + Sn2+
For the values of...
Oh hi there, first post. I'm looking into electrochemical cells and using to the nernst equation to predict cell potential values, and came across a few threads on the topic already on this forum (although none really answered my question), so thought this would be the place to ask.
I know...
Hi All,
From this page:
http://chemwiki.ucdavis.edu/Analytical_Chemistry/Electrochemistry/Electrochemistry_4%3a_The_Nernst_Equation
and this paragraph:
The Nernst equation works only in dilute ionic solutions
Does it mean that the Nernst equation is only accurate for solutions where...
The equation ΔG=-nFEcell, I understand.
I also understand that, at unity activities of all species, Q=1 so R*T*ln(Q)=R*T*ln(1)=0. And therefore Ecell=E°cell and ΔG=ΔG°.
However, surely we cannot then write that ΔG°=-nFE°cell=-R*T*ln(K), since ΔG° is measured at unity activity when Q=1, rather...
Homework Statement
Consider a Galvanic cell made of two half cells:
Ag+ + e− → Ag(s) +0.799 V
Cd2+ + 2e− → Cd(s) − 0.403 V
(a) Calculate the open circuit potential, when the concentration of Ag+ 0.08 mol and the concentration of the Cd2+ is 0.8 mol.
(b) Calculate the voltage across the...
One thing that always puzzled me on the Nerst equation is that you may mix the units of concentration and pressure. This, however, seems to be rather arbitrary. How can using the units of mol/L and atm in the same equation result in accurate results? It seems to be rather arbitrary...
A rather tame ltxnsp was recently found on Easter Island by a retired neurophysiologist. He reported the following measurements of ECF and ICF concentrations (in millimoles):
ICF ECF
Pr+ 0 150
Na+ ? ?
K+ 10 100
Cl- 109 250
HCO3- 1 10
so this is the question: He lacked the proper...
Homework Statement
For a cell in which the reaction Zn(s)+ Ni^2+(aq)->Ni(s)+ Zn^2+(aq) calculate the E(cell) when [Ni^2+]=0.05M, [Zn^2+]=0.85M.
Then, find the ratio of [Ni^2+]/[Zn^2+], when the cell is "flat"
Homework Equations
The simplified nernst equation ...
Homework Statement
The standard reduction potentials for Ni2+ and Sn2+ are as follows:
Ni2+ + 2e− → Ni E° = −0.23 V
Sn2+ + 2e− → Sn E° = −0.14 V
Calculate the equilibrium constant at 25°C for the reaction Sn2+(aq) + Ni(s)→ Sn(s) + Ni2+(aq)
Homework Equations
Nernst...
This problem is homework from a lab I did yesterday. Normally I would just ask my TA, but since it's homework I can't. I could email him, but I feel like I'll probably get a faster response if I post this here
Homework Statement
Use the Nernst equation to determine the cell potential for...
The nernst equation has a log Q term. The denominator of that could be very close to zero. That would make Q close to infinity and log Q close to infinity. How high can the EMF be due to concentration in the real world and why?
Homework Statement
Use the Nernst equation and data from Appendix D in the textbook to calculate E cell for each of the following cells.
Mg(s)|Mg+2 (0.012 M) || [Al(OH)4]- (0.25M), OH- (0.048M)|Al(s)
Homework Equations
Ecell = Ecell(standard) - 0.0591/n * log Q
The Attempt...
The redox midpoint potential (Eo’) of NAD+/NADH at pH 7.0 is -320 mV. If the total concentration of {[NAD+] + [NADH]} is 1.5 mM in cells, and the cellular redox potential is about -200 mV, what are the concentrations of [NAD+] and [NADH], respectively? Under certain oxidative stress...
Homework Statement
Electrochemistry - Nernst Equation
Pb2+ + 2 e- → Pb (s) ξo = -0.13 V
Ag+ + 1 e- → Ag (s) ξo = 0.80 V
What is the voltage, at 298 K, of this voltaic cell starting with the
following non-standard concentrations:
[Pb2+] (aq) = 0.08 M
[Ag+] (aq) = 0.5 M
Homework...
[SOLVED] Nernst Equation Applied to Half-Reactions
The Nernst equation can be applied to half-reactions.
Calculate the reduction potential (at 25°C) of the half-cell
Cu/Cu2+ (1.9×10-4 M).
(The half-reaction is Cu2+ + 2e- --> Cu. E° = 0.34 V)
0.34-[ (8.314)(298)/ (2)(96485)] *...
Can anyone check if I am doing this right?
Given:
Pb2+ + 2e- ---> Pb(s) E standard = -0.13V
Ag+ + 1e- ---> Ag(s) E standard = 0.80V
[Pb2+] = 0.05M
[Ag+] = 0.5 M these are non standard concentrations
Temp = 298K
Using the Nernst equation, find E
My answer:
Pb...
Nernst equation:
\DeltaG = -2.3 RT log10 \frac{C_o}{C_i} + zFV
R = 1.98x10-3 kcal/°K mole
T = absolute temperature in °K (37°C= 310 °K)
Co= concentration dissolved compound outside of cell
Ci= concentration dissolved compound inside of cell
z = the charge of the dissolved compound to...