My teacher went over it really fast and now I'm just really confused about how to do my homework =(

Calculate the cell potential for the following reaction as written at 25C, given that [Cr2+] = 0.821 M and [Ni2+] = 0.0190 M.
Cr(s) + Ni2+ (aq) <==>Cr2+ (aq) + Ni(s)

Thank you in advance!

Look up the Cr and Ni potentials and write the half reaction they represent and we can go through it. It won't help for me to use potentials I look up for our texts may not the same.

To calculate the cell potential for the given reaction, you need to use the Nernst equation. The Nernst equation relates the cell potential to the concentrations of the species involved in the reaction.

The Nernst equation is given as follows:

Ecell = E°cell - (RT/nF) * ln(Q)

Where:
- Ecell is the cell potential
- E°cell is the standard cell potential (usually given in the problem or can be looked up in tables)
- R is the gas constant (8.314 J/(mol·K))
- T is the temperature in kelvin (25 °C = 298 K)
- n is the number of electrons transferred in the balanced equation
- F is the Faraday constant (96485 C/mol)
- Q is the reaction quotient, which is the ratio of product concentrations over reactant concentrations raised to their stoichiometric coefficients

In this case, the balanced equation is:

Cr(s) + Ni2+ (aq) ⇌ Cr2+ (aq) + Ni(s)

Looking at the balanced equation, we can see that the number of electrons transferred (n) is 2.

First, you need to calculate the reaction quotient (Q) using the given concentrations. The ratio of product concentrations over reactant concentrations is:

Q = [Cr2+][Ni(s)] / [Cr][Ni2+]

Substituting the given concentrations:

Q = (0.821 M)(1) / (1)(0.0190 M)

Simplifying:

Q = 43.2105

Now you have all the values needed to calculate the cell potential using the Nernst equation (assuming you have the standard cell potential, E°cell). Just insert the values into the equation and solve for Ecell.