What is the standard cell potential (E°) for a galvanic cell with half-reactions: Zn²⁺ + 2e⁻ → Zn (E° = -0.76 V) and Cu²⁺ + 2e⁻ → Cu (E° = +0.34 V)?
Practice Questions
1 question
Q1
What is the standard cell potential (E°) for a galvanic cell with half-reactions: Zn²⁺ + 2e⁻ → Zn (E° = -0.76 V) and Cu²⁺ + 2e⁻ → Cu (E° = +0.34 V)?
-1.10 V
-0.42 V
0.42 V
1.10 V
E°cell = E°cathode - E°anode = 0.34 V - (-0.76 V) = 1.10 V.
Questions & Step-by-step Solutions
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Q
Q: What is the standard cell potential (E°) for a galvanic cell with half-reactions: Zn²⁺ + 2e⁻ → Zn (E° = -0.76 V) and Cu²⁺ + 2e⁻ → Cu (E° = +0.34 V)?
Solution: E°cell = E°cathode - E°anode = 0.34 V - (-0.76 V) = 1.10 V.
Steps: 6
Step 1: Identify the half-reactions and their standard potentials. The half-reaction for zinc is Zn²⁺ + 2e⁻ → Zn with E° = -0.76 V. The half-reaction for copper is Cu²⁺ + 2e⁻ → Cu with E° = +0.34 V.
Step 2: Determine which half-reaction is the cathode and which is the anode. The cathode is where reduction occurs (gaining electrons), and the anode is where oxidation occurs (losing electrons). Since Cu²⁺ has a higher E° value (+0.34 V), it is the cathode. Zn is the anode.
Step 3: Use the formula for calculating the standard cell potential (E°cell). The formula is E°cell = E°cathode - E°anode.
Step 4: Substitute the values into the formula. E°cell = 0.34 V - (-0.76 V).
Step 5: Simplify the equation. Subtracting a negative is the same as adding, so E°cell = 0.34 V + 0.76 V.
Step 6: Calculate the final value. E°cell = 1.10 V.
