1. Would the cell potential be higher or lower if the NH3(aq) had been added to

Question

1. Would the cell potential be higher or lower if the NH3(aq) had been added to 1M CuSO4 solution instead of the 0.001M CuSO4 solution of the cell? Explain.

2. As the concentration of copper(II) ion increased from 0.0000001M to 0.1M, the cell potential increased. Explain why the change occurred.

3. Suppose the 0.1 M Zn^2+ solution had been diluted (instead of the Cu^2+ solution), would the measured cell potentials have increased or decreased? Explain why the change occurred.

4. How would you increase or decrease the Cu^2+ concentration and/or increase or decrease the Zn^2+ concentration to maximize the cell potential? Explain how the change for each ion woulf maximize the cell potential.

Explanation / Answer

Q1.

Cell potential depends on the concentration of the materials, if we lower NH3, then H+ ions incrase so:

Ecell = E°std -0.0592/n * log(Q)

where

q = reaction/production potential

Q = [H+] and [Cu+2] dependent

If CuSO4 is oxidizing, then increase of CuSO4 favours the Ecell

Q2.

As stated before,

if CuSO4 is reacting, i.e reducing, then if we increase its concentration, we will favour the process

so

Q decreases... meaning that log(Q) decreases as well so

Ecell = E°std - (-x) is actually an increase in Ecell

Q3

Zn2+ + 2 e Zn(s) 0.7618

Cu2+ + 2 e Cu(s) +0.337

Since Zn+2 has a lower potential, this means that it will oxidize,

if we dilute this, this means concentration drops... if concentration of the product drop, this will FAVOUR cell production, i.e. the shift goes toward more Zn+2 produciton (from soldi zinc)

Q4

You can do this via:

ZnCl2 salt = will make Zn+2 and 2Cl- ions in solution

For a decrase in solutions, simply add:

PO4-3 to form Zn3(PO4)3 which will precipitate, therefore decrease Zn+2 ion solution

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.