Calculate the emf of the cell at 25 °C: Zn(s) | (0.01 M) || (1.0 M) | Cu(s). Standard potentials: = -0.76 V, = +0.34 V. Use the Nernst equation.
Answer
1.16 V
The correct answer is 1.16 V — Round the result to two decimal places.
Step-by-step solution
- Write the overall cell reaction: Zn(s) + + Cu(s).
- Identify that the number of electrons transferred, n, is 2.
- Calculate the standard cell potential: E°_cell = = 0.34 - (-0.76) = 1.10 V.
- Apply the Nernst equation: E = E° - (0.0592/n) log([]/[]).
- Insert the concentrations: log([]/[]) = log(0.01/1) = log(0.01) = -2.
- Compute the correction term: (0.0592/2)(-2) = -0.0592 V, so E = 1.10 - (-0.0592) = 1.1592 V.
- Round the result to two decimal places.
Common mistake: Using the concentration quotient as []/[] instead of the correct ratio
Concept tested: Nernst equation for cell potential
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