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V. Concentration Cell Copper - Copper Cu(s), CuCl2 (0.01 ) || Cu (s), CuCl2 (1.0

ID: 1055624 • Letter: V

Question

V. Concentration Cell

Copper - Copper

Cu(s), CuCl2 (0.01) || Cu(s), CuCl2 (1.0 M)

4. Calculate E°cell of this electrochemical cell. (include units)

E°cell   _______0.00___________________

5. Calculate the reaction quotient (Q) of this reaction.

Q ___0.01___________________

6. Calculate the expected Ecell for this reaction.

Ecell ___0.0592___________________

7. Record the value of the measured Ecell

Ecell ____53.4______________

8. Calculate the percent error

% error __________________

The answers in bold are what I calculated but I'm confused because my measured value is so large and leaves a percent error of about 90100%! Am I doing something wrong or was there just error in my measured Ecell?

Explanation / Answer

E°cell = 0 by definition

Q = [Cu+2]/[Cu+2]

Q = 0.01/1 = 0.01

so

Ecell = E°cell - 0.0592/n*log(Q)

Ecell = 0 - 0.0592/2*log(0.01) = 0.0592 V

Q7

most likely... you mearued the volatage in mili volts... so 53.4 mvolts --> 53.4*10^-3 volts = 0.0534 V, which is what we expected

% error = real - measurea / real * 100% = (0.0592 -0.0534 -)/0.0592 * 100 = 9.79729% error!