10 Questions
What is the transfer involved in an electric current?
Electrons
What happens during a redox reaction?
Electrons are transferred
What is the term used to describe the potential difference between a metal and a solution?
Electrode potential
Which force is responsible for the tendency of Mn+ ions to deposit on the metal rod in a redox system?
Ionic pressure
What kind of charge does the metal rod acquire when it has high solution pressure?
-ve charge
In half-cell reactions, what is the sign of the electrode potential for metals that tend to lose electrons?
-ve sign
What happens when a metal like Zn° is converted to its ions in a redox system?
+ve ionic pressure, -ve solution pressure
What does the term EMF stand for in the context of electrode potential?
Electromotive Force
Which element would have high solution pressure according to the text?
[Zn0]
What does a metal rod acquire when the tendency of Mn+ ion to deposit on it increases?
+ve charge
Study Notes
Electrode Potential
- Electrode potential is the potential difference between a metal and its ions in a solution
- It is measured in an electrochemical cell using a reference electrode with a known potential
- The potential of a single electrode cannot be measured directly, but can be measured against a reference electrode
Nernst Equation
- The Nernst equation is used to calculate the electrode potential at 25°C
- The equation is: E25°C = Eo + 0.059 Log [Mn+]/n
- Where: E25°C is the electrode potential at 25°C, Eo is the standard electrode potential, [Mn+] is the molar concentration of metal ions, and n is the number of electrons gained or lost
Standard Hydrogen Electrode
- The standard hydrogen electrode is a reference electrode with a known and fixed potential
- Its potential is considered zero, and is used as a standard against which other electrode potentials are measured
Types of Electrode Potential
- Positive electrode potential: occurs when the metal has a high ionic pressure, e.g. Cu, Hg, Ag
- Negative electrode potential: occurs when the metal has a high solution pressure, e.g. Zn, Fe, Co, Ni
Measurement of Electrode Potential
- Electrode potential is measured using an electrochemical cell with two electrodes: one is the electrode being measured, and the other is a reference electrode
- The two electrodes are joined by a salt bridge, which allows the transfer of electric current between the solutions in the electrodes
- The direction of electron flow is from the electrode with a negative potential to the electrode with a positive potential
Test your knowledge on calculating electrode potential using the Nernst equation for Metal/Metal ion systems. Learn about oxidation, reduction, electron production, and understanding signs in electrochemistry.
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