How to calculate Q in Nernst Equations, we used 0.10M solutions in all of our half cells.

Nernst equation:

Ecell = E0cell - RT/nF ln Q

Overall reactions:
Cu(s) + Pb2+(aq) ~ Cu2+(aq) + Pb(s)

and

3Pb(s) + 2Al3+ ~ 3Pb2+ 2Al(s)

Thank you!

To calculate Q in the Nernst equation, you need to understand the concept of reaction quotients. The reaction quotient (Q) is a measure of the relative concentrations of the reactants and products in a chemical reaction at a given point in time.

In your case, you have two half-cell reactions you need to consider:

1) Cu(s) + Pb2+(aq) → Cu2+(aq) + Pb(s)
2) 3Pb(s) + 2Al3+ → 3Pb2+ + 2Al(s)

To calculate Q for each half-reaction, you need to determine the concentration of each species involved. You mentioned that you used 0.10M solutions in all the half-cells, so we can assume that the concentrations of the species are 0.10M.

For the first half-reaction, Q = [Cu2+]/[Pb2+]. Since the concentration of both Cu2+ and Pb2+ is 0.10M, we can substitute these values into the equation: Q = (0.10M)/(0.10M) = 1.

For the second half-reaction, Q = [Pb2+]^3/[Al3+]^2. Again, since the concentration of both Pb2+ and Al3+ is 0.10M, we can substitute these values into the equation: Q = (0.10M)^3/(0.10M)^2 = 1.

After calculating Q for each half-reaction, you can then use these values in the Nernst equation. The Nernst equation is given by:

Ecell = E0cell - (RT/nF) × lnQ

Here, Ecell is the cell potential, E0cell is the standard cell potential, R is the ideal gas constant (8.314 J/(mol·K)), T is the temperature in Kelvin, n is the number of moles of electrons transferred in the balanced equation, F is the Faraday constant (96485 C/mol), and lnQ is the natural logarithm of the reaction quotient.

Note: The values of E0cell, R, and F are constant, and you will need to determine their specific values depending on the reaction and conditions you are working with.

By plugging in the calculated values of Q, as well as the other known values, you can solve for Ecell in the Nernst equation.