Questions tagged [nernst-equation]

For questions regarding when and how to use the Nernst equation or exploring the theory by the equation.

7
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1answer
310 views

Is there a better equation than the Nernst equation for low concentrations?

The Nernst equation can be applied to the whole cell reaction or a half-cell reaction. Consider the half cell reaction: $$\ce{Cu^{2+} + 2e^- -> Cu(s) \quad \quad E^0 = +0.337~\rm{V}}$$ The Nernst ...
4
votes
1answer
382 views

Do I use the Nernst equation when the concentrations of electrolyte in both half cells are equal?

I'm doing a chemistry report, and for my experiment I investigated the amount of voltage produced by different half cells in a voltaic cell. However, I tested them under nonstandard conditions as ...
3
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2answers
129 views

Proof of the chemical potential formula

My textbook as well as Wikipedia both state the formula $\mu_A = \mu_A^0 + RT\ln\{A\}$ which gives the chemical potential $\mu_A$ of a chemical species $A$ as function of the standard chemical ...
3
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1answer
90 views

A contradiction regarding the reaction coefficient expression in the Nernst equation

I came up with the following question in my NCERT textbook: Write the Nernst equation and the emf of the following cell at $\pu{298 K}$. $$\ce{Fe}|\ce{Fe^2+}(\pu{0.001 M})||\ce{H+}(\pu{1 M})|\...
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2answers
134 views

Calculate the cathode electrode potential in this redox reaction

In this problem I'm asked to calculate the electrode potential of the magnesium electrode ($E_{Mg^{2+}/Mg}$) given the red-ox reaction:$$\text{Mg(s)}+2\text{Ag}^+(10^{-2}\text{M})\leftrightarrow 2\...
1
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1answer
1k views

What pressure units should be used when calculating electrode potential with Nernst equation?

Example 17: Calculate the electrode potential of given electrode $$\ce{Pt,Cl2 (\pu{1.5 bar}) | 2 Cl- (\pu{0.01 M})}\,; \quad E^\circ_\ce{Cl2/2Cl-} = \pu{1.36 V}$$ Solution: The reaction of ...
1
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1answer
259 views

What exactly is Q in the Nerst equation for a ¨lemon battery¨ of Cu and Zn in varying concentrations of acid?

I want to vary $\ce{[H+]}$ and see its affect on the voltage produced by a Zn-Cu in acid "lemon battery". My question is about the expression for $Q$ in the Nernst equation for this cell. I think $Q$...
1
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2answers
362 views

Nernst equation calculations

I am stuck on 2 problems and would be grateful if anyone decided to give me a proper explanation as to how to solve them. I am not sure how to use the given information to correctly solve what is ...
1
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1answer
155 views

Voltaic cell and Nernst equation

It is given voltaic cell $\ce{Cu}|\ce{CuSO4}(\pu{10^-3 M})||\ce{CH3COONa}(10^{-2})|\ce{Pt}(\ce{H2})(\pu{1 atm})$. Find the potential at $\pu{50^\circ C}$. Given $K_\mathrm{a}$ for $H= 1.8 \times ...
1
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1answer
4k views

Calculating the EMF of cell

Find the EMF of the following cell : $$\ce{Pb(s)}, \ce{PbSO_4}|\ce{SO_4^{2-}}(\pu{0.100M})||\ce{Pb^{2+}}(\pu{0.004M})|\ce{Pb(s)}$$ Given: $E^0_{\ce{PbSO_4|Pb,SO_4^{2-}}}=\pu{-0.359V}$ and $E^0_{...
0
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1answer
488 views

N in Nernst Equation [closed]

My teacher told me that in the Nernst equation, N was the number of electrons transferred. For example, $n = 2$ in $\ce{Ni^{2+} + Zn -> Zn^{2+} + Ni}$. However, say all of the coefficients were ...
0
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1answer
290 views

How the Nernst equation is applied for electrodeposition? [closed]

For using the Nernst equation $$E = E_0 - \frac{RT}{nF}\ln\frac{[\ce{Red}]}{[\ce{Ox}]}$$ the concentrations of $\ce{Red}$ and $\ce{Ox}$ species are required. For the reaction $$\ce{Cu+ + e- <=&...
0
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1answer
932 views

Is equilibrium potential for K+ always ~-90 mV?

Equilibrium potential is the difference in charge relative to the inside of the cell. -90 mV means that the inside of a cell is more negative than the outside. However when you talk about equilibrium ...
0
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0answers
37 views

Why is the reaction quotient Q always equal to one at standard state?

I understand that at equilibrium, $Q$ is equal to $K$. This should not depend how I express concentrations (as amount of substance concentrations $c$ or as partial pressures $p$ or as molality $b$ or ...
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0answers
35 views

Theoretical Calculations for Potential Generated in Salt Water Battery

I am using a $\pu{1.5 M}~\ce{KCl}$ solution as electrolyte and copper and aluminium electrodes but no salt bridge. So basically there is only one beaker with the two electrodes in it with the $\pu{1.5 ...
0
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0answers
477 views

Concentration of gas phase in Nernst equation

What if one or both electrodes are in gas phase? Use PV=nRT? Also the definition of hydrogen electrode gets a little sketchy if we use PV=nRT to write it's concentration, the electrode potential doesn'...