What are \(E_{\text {cell }}^{\circ}\) and \(\Delta G^{\circ}\) of a redox reaction at \(25^{\circ} \mathrm{C}\) for which \(n=2\) and \(K=65 ?\)

Short Answer

Expert verified
The standard cell potential (\( E_{\text{cell}}^{\text{o}} \)) is approximately 0.0537 V, and the standard Gibbs free energy change (\( \Delta G^{\text{o}} \)) is about -10.4 kJ/mol.

Step by step solution

01

- Write the Nernst Equation

To find the standard cell potential, write the equation: \[ E_{\text {cell }}^{\text { }}=\frac{0.0592}{n} \times \text{log}(K) \].
02

- Substitute the Given Values

Substitute the given values into the equation: \[ E_{\text{cell}}^{\text{o}} = \frac{0.0592}{2} \times \text{log}(65) \].
03

- Calculate the Logarithm

Calculate \( \text{log}(65) \): \[ \text{log}(65) \approx 1.813 \].
04

- Compute the Standard Cell Potential

Compute the standard cell potential by multiplying: \[ E_{\text{cell}}^{\text{o}} = \frac{0.0592}{2} \times 1.813 \approx 0.0537 \text{ V} \].
05

- Use the Relationship Between \( \Delta G^{\text { }} ~and~ E_{\text{cell}}^{\text{o}} \)

Use the formula: \[ \Delta G^{\text{o}} = -nFE_{\text{cell}}^{\text{o}} \]. Here, \( F \approx 96485 \text{ C/mol} \) and \( n=2 \).
06

- Substitute the Values for \( \Delta G^{\text{o}} \)

Substitute the values into the equation: \[ \Delta G^{\text{o}} = -2 \times 96485 \text{ C/mol} \times 0.0537 \text{ V} \].
07

- Compute \( \Delta G^{\text{o}} \)

Compute \( \Delta G^{\text{o}} \): \[ \Delta G^{\text{o}} \approx -2 \times 96485 \times 0.0537 \approx -10363 \text{ J/mol} \approx -10.4 \text{ kJ/mol} \].

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with Vaia!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Redox reaction
A redox reaction, short for reduction-oxidation reaction, involves the transfer of electrons between two species. During this process, one substance gets oxidized (loses electrons) while another gets reduced (gains electrons). Understanding redox reactions is essential because they form the basis of many chemical processes and are fundamental in electrochemistry. You can identify redox reactions with changes in oxidation states of the elements involved.

In the context of electrochemistry, redox reactions occur in electrochemical cells where oxidation happens at the anode and reduction at the cathode. These reactions generate electrical energy in galvanic cells or consume electrical energy in electrolytic cells.

Remember, balancing redox reactions requires ensuring both mass and charge are conserved. You may use methods like the half-reaction method to split into oxidation and reduction parts, balance them independently, and then combine them for the full reaction.
Standard cell potential
Standard cell potential (\(E_{\text{cell}}^\text{o}\)) is a measure of the potential difference between two half-cells under standard conditions (1 M concentration, 1 atm pressure, and 25°C). It determines how much voltage an electrochemical cell can provide. The Nernst equation gives us a useful way to find this potential:

\begin{align*}E_{\text{cell}} = E_{\text{cell}}^\text{o} - \frac{0.0592}{n} \text{log}(Q)\text{/end{align*}In the exercise example, we used a variation of this equation to find the standard cell potential. By knowing the equilibrium constant (\text{K}), we can simplify our work:\begin{align*}E_{\text{cell}}^\text{o} = \frac{0.0592}{n} \times \text{log}(K)//end{align*} where n is the number of moles of electrons transferred. Substituting the given values from the exercise determined the standard cell potential for the reaction.A positive (\text{E\text{cell}}\text{o}) indicates a spontaneous redox reaction.
Gibbs free energy
Gibbs free energy (\text{G}) determines whether a process is spontaneous. For redox reactions, the change in Gibbs free energy (\text{\(\text{Delta} G\)}) links directly to the cell potential using the equation:

\begin{align*}\text{\(\text{Delta} G\)}^\text{o} = -nFE_{\text{cell}}^\text{o}\text{end{align*}\text{Here, F} is the Faraday constant (about 96485 C/mol).Replacing the values from the example into this equation allows us to calculate the Gibbs free energy change for the redox reaction.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

A voltaic cell consists of two \(\mathrm{H}_{2} / \mathrm{H}^{+}\) half-cells. Half-cell \(\mathrm{A}\) has \(\mathrm{H}_{2}\) at 0.95 atm bubbling into \(0.10 \mathrm{M} \mathrm{HCl}\). Half-cell \(\mathrm{B}\) has \(\mathrm{H}_{2}\) at 0.60 atm bubbling into \(2.0 \mathrm{M} \mathrm{HCl}\). Which half-cell houses the anode? What is the voltage of the cell?

Write a balanced half-reaction for the product that forms at each electrode in the aqueous electrolysis of the following salts: (a) \(\mathrm{Cr}\left(\mathrm{NO}_{3}\right)_{3} ;\) (b) \(\mathrm{MnCl}_{2}\).

The \(\mathrm{MnO}_{2}\) used in alkaline batteries can be produced by an electrochemical process of which one half-reaction is $$\mathrm{Mn}^{2+}(a q)+2 \mathrm{H}_{2} \mathrm{O}(l) \longrightarrow \mathrm{MnO}_{2}(s)+4 \mathrm{H}^{+}(a q)+2 \mathrm{e}^{-}$$ If a current of \(25.0 \mathrm{~A}\) is used, how many hours are needed to produce \(1.00 \mathrm{~kg}\) of \(\mathrm{MnO}_{2} ?\) At which electrode is the \(\mathrm{MnO}_{2}\) formed?

Brass, an alloy of copper and zinc, can be produced by simultaneously electroplating the two metals from a solution containing their \(2+\) ions. If \(65.0 \%\) of the total current is used to plate copper, while \(35.0 \%\) goes to plating zinc, what is the mass percent of copper in the brass?

Balance the following skeleton reactions, and identify the oxidizing and reducing agents: (a) \(\mathrm{As}_{4} \mathrm{O}_{6}(s)+\mathrm{MnO}_{4}^{-}(a q) \longrightarrow \mathrm{AsO}_{4}^{3-}(a q)+\mathrm{Mn}^{2+}(a q)\) [acidic] (b) \(\mathrm{P}_{4}(s) \longrightarrow \mathrm{HPO}_{3}^{2-}(a q)+\mathrm{PH}_{3}(g)\) [acidic] (c) \(\mathrm{MnO}_{4}^{-}(a q)+\mathrm{CN}^{-}(a q) \longrightarrow \mathrm{MnO}_{2}(s)+\mathrm{CNO}^{-}(a q)\) [basic]

See all solutions

Recommended explanations on Chemistry Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free