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Ch.20 - Electrochemistry
Brown - Chemistry: The Central Science 15th Edition
Brown15th EditionChemistry: The Central ScienceISBN: 9780137542970당신이 사용하는 게 아니라요?교과서 변경
모든 교과서Brown 15th EditionCh.20 - Electrochemistry문제 104a
20장, 문제 104a

A voltaic cell is constructed that uses the following half-cell reactions:
Cu+(aq) + e- → Cu(s)
I2(s) + 2 e- → 2 I-(aq)
The cell is operated at 298 K with [Cu+] = 0.25 M and [I-] = 0.035 M.
(a) Determine E for the cell at these concentrations.

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1
Identify the oxidation and reduction half-reactions. In this case, Cu+ is reduced to Cu(s) and I2(s) is oxidized to I-.
Write the balanced overall cell reaction by combining the half-reactions. Ensure that the number of electrons lost in oxidation equals the number of electrons gained in reduction.
Use the Nernst equation to calculate the cell potential (E) at non-standard conditions. The Nernst equation is: E = E^0 - (RT/nF) * ln(Q), where E^0 is the standard cell potential, R is the gas constant (8.314 J/mol·K), T is the temperature in Kelvin, n is the number of moles of electrons transferred, F is the Faraday constant (96485 C/mol), and Q is the reaction quotient.
Calculate the reaction quotient, Q, from the given concentrations. For the reaction Cu+ + I2 -> Cu + 2 I-, Q is calculated as Q = [I-]^2 / [Cu+].
Substitute the values of E^0, R, T, n, F, and Q into the Nernst equation to find the cell potential E.

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주요 개념

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Electrochemical Cells

Electrochemical cells, such as voltaic cells, convert chemical energy into electrical energy through redox reactions. In a voltaic cell, oxidation occurs at the anode and reduction at the cathode, allowing for the flow of electrons through an external circuit. Understanding the setup and function of these cells is crucial for analyzing their behavior under different conditions.
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가이드 코스
02:46
Electrochemical Cells

Nernst Equation

The Nernst equation relates the cell potential (E) to the concentrations of the reactants and products in a redox reaction. It is expressed as E = E° - (RT/nF) ln(Q), where E° is the standard cell potential, R is the gas constant, T is the temperature in Kelvin, n is the number of moles of electrons transferred, F is Faraday's constant, and Q is the reaction quotient. This equation is essential for calculating the cell potential under non-standard conditions.
추천 영상:
가이드 코스
01:17
The Nernst Equation

Reaction Quotient (Q)

The reaction quotient (Q) is a measure of the relative concentrations of reactants and products at any point in a reaction. It is calculated using the formula Q = [products]/[reactants], with each concentration raised to the power of its stoichiometric coefficient. In the context of the Nernst equation, Q helps determine how the cell potential changes as the reaction progresses and concentrations vary.
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00:49
Reaction Quotient Q
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교과서 질문

A voltaic cell is constructed that uses the following half-cell reactions:

Cu+(aq) + e- → Cu(s)

I2(s) + 2 e- → 2 I-(aq)

The cell is operated at 298 K with [Cu+] = 0.25 M and [I-] = 0.035 M.

(b) Which electrode is the anode of the cell?

(c) Is the answer to part (b) the same as it would be if the cell were operated under standard conditions?

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