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Ch.19 - Electrochemistry
Tro - Chemistry: A Molecular Approach 4th Edition
Tro4th EditionChemistry: A Molecular ApproachISBN: 9780134112831Non è quello che usi tu?Cambia libro di testo
Capitolo 19, Problema 78a

A voltaic cell consists of a Pb/Pb2+ half-cell and a Cu/Cu2+ half-cell at 25°C. The initial concentrations of Pb2+ and Cu2+ are 0.0500 M and 1.50 M, respectively. a. What is the initial cell potential?

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Identify the standard reduction potentials for both half-reactions. For Pb, the reaction is Pb^2+ + 2e^- -> Pb, and for Cu, the reaction is Cu^2+ + 2e^- -> Cu.
Determine the direction of electron flow by comparing the standard reduction potentials. Electrons flow from the anode (where oxidation occurs) to the cathode (where reduction occurs).
Calculate the standard cell potential (E°_cell) using the formula E°_cell = E°_cathode - E°_anode, where E°_cathode and E°_anode are the standard reduction potentials of the cathode and anode, respectively.
Use the Nernst equation to find the actual cell potential under non-standard conditions. The Nernst equation is E_cell = E°_cell - (RT/nF) * ln(Q), where R is the gas constant, T is the temperature in Kelvin, n is the number of moles of electrons transferred, F is the Faraday constant, and Q is the reaction quotient.
Calculate the reaction quotient (Q) using the initial concentrations of the ions involved in the cell reactions. For this cell, Q = [Pb^2+]/[Cu^2+].

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Voltaic Cell

A voltaic cell, also known as a galvanic cell, is an electrochemical cell that converts chemical energy into electrical energy through spontaneous redox reactions. It consists of two half-cells, each containing an electrode and an electrolyte. The flow of electrons from the anode to the cathode generates an electric current, and the cell potential is determined by the difference in reduction potentials of the two half-reactions.
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The Electrolytic Cell

Nernst Equation

The Nernst equation relates the cell potential 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 universal 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 allows for the calculation of the cell potential under non-standard conditions.
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The Nernst Equation

Standard Reduction Potentials

Standard reduction potentials are measured voltages that indicate the tendency of a species to gain electrons and be reduced, measured under standard conditions (1 M concentration, 1 atm pressure, and 25°C). Each half-reaction has a specific standard reduction potential, and the overall cell potential can be calculated by subtracting the anode potential from the cathode potential. These values are crucial for determining the feasibility and strength of the electrochemical reaction.
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Standard Reduction Potentials
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Domanda del libro di testo

A voltaic cell consists of a Pb/Pb2+ half-cell and a Cu/Cu2+ half-cell at 25°C. The initial concentrations of Pb2+ and Cu2+ are 0.0500 M and 1.50 M, respectively. b. What is the cell potential when the concentration of Cu2+ has fallen to 0.200 M?

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Domanda del libro di testo

A voltaic cell consists of a Zn/Zn2+ half-cell and a Ni/Ni2+ half-cell at 25 °C. The initial concentrations of Ni2+ and Zn2+ are 1.50 M and 0.100 M, respectively. c. What are the concentrations of Ni2+ and Zn2+ when the cell potential falls to 0.45 V?

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Domanda del libro di testo

A voltaic cell consists of a Zn/Zn2+ half-cell and a Ni/Ni2+ half-cell at 25 °C. The initial concentrations of Ni2+ and Zn2+ are 1.50 M and 0.100 M, respectively. b. What is the cell potential when the concentration of Ni2+ has fallen to 0.500 M?

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Domanda del libro di testo

A voltaic cell consists of a Pb/Pb2+ half-cell and a Cu/Cu2+ half-cell at 25°C. The initial concentrations of Pb2+ and Cu2+ are 0.0500 M and 1.50 M, respectively. c. What are the concentrations of Pb2+ and Cu2+ when the cell potential falls to 0.35 V?

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Domanda del libro di testo

Make a sketch of a concentration cell employing two Zn/Zn2+ half-cells. The concentration of Zn2+ in one of the half-cells is 2.0 M and the concentration in the other half-cell is 1.0×10–3 M. Label the anode and the cathode and indicate the half-reaction occuring at each electrode. Also indicate the direction of electron flow.

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Domanda del libro di testo

A voltaic cell consists of a Zn/Zn2+ half-cell and a Ni/Ni2+ half-cell at 25 °C. The initial concentrations of Ni2+ and Zn2+ are 1.50 M and 0.100 M, respectively. a. What is the initial cell potential?

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