A concentration cell based on the following half reaction at 280 K
Cu2+ +2e Cu has initial concentrations of 1.37 Cu 2+, 0.215 Cu2+, and a potential of 0.02314 V at these conditions. After 9.1 hours, the new potential of the cell is found to be 0.009826 V. What is the concentration of Cu2+ at the cathode at this new potential?
a. 0.697
b. 0.871
c. 1.09
d. 1.36
e. 1.70
What is the concentration of Cu2+ at the cathode at this new potential?
a. 0.697
b. 0.871
c. 1.09
d. 1.36-answer
e. 1.70
Cu2+(aq) + 2e----------à Cu(s) (cathode)
Cu(s) ------à Cu2+(aq) + 2e- (anode)
The standard electrode potential E° = 0 V and the potential can be calculated using the Nernst equation for this 2 electron reaction, n = 2:
E = E° − RT/nF lnQ
= -RT/nF ln ([Cu2+ anode / Cu2+ cathode )
= -(8.314 *280/ (2 *96485) ln ([Cu2+ anode / 0.02314 ) = 0.009826 V.
What is the concentration of Cu2+ at the cathode = 1.36
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