Question

what is the standard free energy (∆g°) of the reaction represented by the cell shorthand notation Pt | Fe²+ , Fe³+ || Ag+ | Ag

Answer 1

The standard free energy change (ΔG°) of the galvanic cell reaction can be calculated using the equation ΔG° = -nFE°, where n is the number of moles of electrons transferred, F is Faraday's constant, and E° is the standard cell potential.

Step-by-step explanation:

Calculating the Standard Free Energy Change (ΔG°)

The student has asked about the standard free energy (Δg°) of the reaction represented by the cell shorthand: Pt | Fe²+ , Fe³+ || Ag+ | Ag. To determine this, we must use the relationship between the standard free energy change, standard cell potential (ΔG° = -nFE°), and the number of moles of electrons transferred in the reaction (n).
`Fe²+ , Fe³+ || Ag+ | Ag\\`

The Faraday's constant (F) is a known value used to convert between electrical energy and chemical energy.

First, we calculate the standard cell potential (E°) for the reaction using the standard potentials of the half-reactions. The half-reactions for this cell are Ag+ + e⁻ → Ag(s) with an E° of +0.80V and Fe³+ + e⁻ → Fe²+ with an E° of +0.77V. The E° cell is the difference between the cathode and anode potentials.

Next, we identify the number of moles of electrons transferred (n) in the balanced equation for the reaction. Lastly, we plug these values into the equation ΔG° = -nFE° to calculate the standard free energy change.

Spontaneity is indicated by a negative ΔG° and a positive E°.

The standard free energy change can also be calculated from standard free-energy of formation values (ΔG°f) of the reactants and products.

Answer 2

The standard free energy change (∆G°) is calculated using the equation ∆G° = -nFE°cell, which considers the standard cell potential (E°cell), the number of moles of electrons (n), and Faraday's constant (F). A positive E°cell results in a negative ∆G°, indicating a spontaneous reaction.

Step-by-step explanation:

The standard free energy change (∆G°) of a reaction can be calculated using the relationship between ∆G° and the standard cell potential (E°cell) as well as the number of moles of electrons transferred in the reaction, represented by n, and Faraday's constant (F). The formula is as follows:

∆G° = -nFE°cell

For the cell represented by the shorthand notation “Pt | Fe²+, Fe³+ || Ag+ | Ag”, we need to calculate the standard cell potential by considering the standard reduction potentials for the cathode and anode. Once E°cell is determined, the number of moles of electrons (n) can be assessed based on the balanced chemical equation, and then ∆G° can be calculated. Remember that a positive E°cell indicates a spontaneous reaction, which correlates to a negative ∆G°.

The equation 2Ag+ (aq) + Fe(s) ⇒ 2Ag(s) + Fe²+ (aq) with a given E°cell of 0.74 V signifies a spontaneous reaction and allows for the calculation of ∆G° using the formula provided. It should be noted that when analyzing the spontaneity, we refer to the standard free energy change, indicating whether the forward reaction, as written, would be spontaneous under standard conditions.