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Questions and Answers
What are the identities and charges of the electrodes in a voltaic cell using Mg and Zn?
What are the identities and charges of the electrodes in a voltaic cell using Mg and Zn?
The anode is magnesium (Mg) with a charge of 0, and the cathode is zinc (Zn) with a charge of +2.
In the voltaic cell, what is the direction of electron flow, and why?
In the voltaic cell, what is the direction of electron flow, and why?
Electrons flow from the magnesium electrode (anode) to the zinc electrode (cathode) due to the higher reduction potential of zinc.
Write down the oxidation reaction occurring at the anode in the voltaic cell.
Write down the oxidation reaction occurring at the anode in the voltaic cell.
The oxidation reaction is: $Mg \rightarrow Mg^{2+} + 2e^{-}$.
What is the reduction reaction occurring at the cathode in the voltaic cell?
What is the reduction reaction occurring at the cathode in the voltaic cell?
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How can standard reduction potentials (E0) be used to predict the flow of electrons in this cell?
How can standard reduction potentials (E0) be used to predict the flow of electrons in this cell?
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Study Notes
Voltaic Cell Setup
- A voltaic cell is constructed with two half-cells.
- One half-cell contains a magnesium electrode (Mg) immersed in a solution of magnesium ions (Mg²⁺).
- The second half-cell contains a zinc electrode (Zn) immersed in a solution of zinc ions (Zn²⁺).
Electrode Characteristics
- Magnesium electrode (Mg): Acts as the anode (negative electrode) where oxidation occurs.
- Zinc electrode (Zn): Acts as the cathode (positive electrode) where reduction occurs.
Electron Flow
- Electrons flow from the anode (Mg) to the cathode (Zn) through an external circuit.
Ion Flow
- Mg²⁺ ions move from the anode compartment to the cathode compartment through a salt bridge or porous membrane.
- Zn²⁺ ions move from the cathode compartment to the anode compartment.
Reactions at the Electrodes
- Anode (oxidation): Mg(s) → Mg²⁺(aq) + 2e⁻ (E° = -2.37 V)
- Cathode (reduction): Zn²⁺(aq) + 2e⁻ → Zn(s) (E° = -0.76 V)
Cell Potential
- The overall cell potential (E°cell) is calculated by subtracting the standard reduction potential of the anode from the standard reduction potential of the cathode.
- E°cell = E°cathode - E°anode = (-0.76 V) - (-2.37 V) = 1.61 V
- The positive value of E°cell indicates that the reaction is spontaneous and the cell can produce electrical energy.
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Description
This quiz explores the structure and functions of a voltaic cell, focusing on the magnesium and zinc electrodes. It covers the processes of oxidation and reduction at each electrode, as well as the flow of electrons and ions. Test your knowledge on the electrochemical principles governing this cell setup.
