Fill in the two blanks Zn^2+ + 2e- rightarrow Zn E = -0.763 Cu^2+ + 2e- rightarr

Question

Fill in the two blanks Zn^2+ + 2e- rightarrow Zn E = -0.763 Cu^2+ + 2e- rightarrow Cu E = 0.337 **Observed potential for the Zn/Zn^2+ 0.1 M||Cu^2+ 0.1M/Cu Percent error from theoretical potential 0.1 M CuS0_4 and unknown ZnS0_4 code and Unknown concentration of ZnSO_4 (Use **observed potential for the Zn/Zn^2+ 0.1 M||Cu^2+ 0.1M/Cu cell as the E degree in the calculation and note the number of significant figures given on reagent bottles.) 0.1 M ZnSO_4 and unknown CuSO_4 code and potential Unknown concentration of CuSO_4 (Use **observed potential for the Zn/Zn^2+ 0.1 M||Cu^2+ 0.1M/Cu cell as the E degree in the calculation note the number of significant figures given on reagent bottles.)

Explanation / Answer

Apply Nernst equation

Ecell = E°cell - 0.0592/n*log(Q)

we need E°Cell so

E°Cell = Ered - Eox

red = Cu 0.337

ox = Zn - 0.763

E°Cell = Ered - Eox = 0.337+0.763 = 1.1

n = 2 mol of e- transferr

Ecell = 1.1- 0.0592/2*log(Zn+2 / Cu+2)

For uknown ZnSO4:

1.047 = 1.1- 0.0592/2*log(Zn+2 / 0.1)

solve for [Zn+2]

(1.047-1.1 )*2/-0.0592 = log(Zn+2 / 0.1)

1.790540 = log(Zn+2 / 0.1)

Zn+2 = 0.1* 10^1.790540 = 6.17362 M

b)

For unkonw Cu+2

1.071= 1.1- 0.0592/2*log(0.1/ Cu+2

log(0.1/[Cu+2]) = (1.071-1.1)*2/(-0.0592)

[cu+2] = 1/(10^0.97972)

[Cu+2] = 0.1047803

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