All Flashcards

Define E°_cell.

Cell potential under standard conditions (298.15 K, 1 atm, 1 M concentrations).

Define E_cell.

Cell potential under non-standard conditions.

Define the reaction quotient, Q.

A measure of the relative amount of products and reactants present in a reaction at a given time. Used to determine if a reaction is at equilibrium.

Define Faraday's constant (F).

The charge of one mole of electrons, approximately 96485 C/mol e-.

Define 'n' in the Nernst Equation.

Moles of electrons transferred in the balanced redox reaction.

How to determine Q for the reaction: $2Al(s) + 3Mn^{2+}(aq) \rightarrow 2Al^{3+}(aq) + 3Mn(s)$ ?

Q = $\frac{[Al^{3+}]^2}{[Mn^{2+}]^3}$

Steps to predict E_cell relative to E°_cell using Q.

How do you calculate E°_cell at equilibrium using the Nernst Equation?

Set E_cell = 0 and Q = K in the Nernst Equation, then solve for E°_cell.

What is the formula of Nernst Equation?

$E_{cell} = E^circ_{cell} - \frac{RT}{nF}lnQ$ or $E_{cell} = E^circ_{cell} - \frac{0.0592}{n}logQ$

How to relate ΔG to E_cell?

ΔG = -nFE_cell

Differentiate between E°_cell and E_cell.

E°_cell: Cell potential at standard conditions. | E_cell: Cell potential at non-standard conditions.

Compare the conditions when Q = 1 versus Q ≠ 1.

Q = 1: Standard conditions, all concentrations are 1 M. | Q ≠ 1: Non-standard conditions, concentrations are not 1 M.

How does Q relate to K at equilibrium and non-equilibrium?

At equilibrium: Q = K. | Non-equilibrium: Q ≠ K.

What is the difference between a voltaic cell at equilibrium and non-equilibrium?

Non-equilibrium: Running galvanic cell, E_cell > 0. | Equilibrium: Dead battery, E_cell = 0.

Compare the effect of Q > 1 and Q < 1 on E_cell.

Q > 1: E_cell < E°_cell. | Q < 1: E_cell > E°_cell.