What do you mean by electrochemical equivalent of Faraday's law of electrolysis?
2 Answers
The electrochemical equivalent of Faraday's law of electrolysis is a concept that quantifies the relationship between the amount of substance transformed during electrolysis and the quantity of electric charge used. It essentially helps in determining how much of a substance is deposited or dissolved in an electrolytic process based on the electric charge passed through the electrolyte.
Here’s a breakdown of the concept:
### Faraday’s Laws of Electrolysis
1. **First Law**: The mass of a substance altered at an electrode during electrolysis is directly proportional to the quantity of electric charge passed through the electrolyte.
Mathematically:
\[
m = k \cdot Q
\]
where \( m \) is the mass of the substance altered, \( Q \) is the electric charge, and \( k \) is a proportionality constant.
2. **Second Law**: The mass of a substance altered at an electrode during electrolysis is proportional to its equivalent weight and the quantity of electric charge passed through the electrolyte.
### Electrochemical Equivalent
The electrochemical equivalent (E) of a substance is the mass of the substance deposited or dissolved when an electric charge of 1 coulomb passes through the electrolyte. It is a measure that connects the amount of substance changed to the amount of electric charge used.
The relationship can be expressed as:
\[
E = \frac{m}{Q}
\]
where \( E \) is the electrochemical equivalent, \( m \) is the mass of the substance deposited or dissolved, and \( Q \) is the quantity of electric charge.
### Calculating Electrochemical Equivalent
To calculate the electrochemical equivalent of a substance, you use Faraday’s law, considering the molar mass (M) of the substance and the number of electrons (n) involved in the electrochemical reaction. The formula is:
\[
E = \frac{M}{n \cdot F}
\]
where:
- \( M \) is the molar mass of the substance.
- \( n \) is the number of electrons involved in the reaction.
- \( F \) is Faraday's constant (approximately 96485 C/mol).
### Practical Example
For instance, in electroplating, if you know the electrochemical equivalent of the metal being deposited, you can calculate how much metal will be deposited for a given charge. If the electrochemical equivalent of a metal is known to be 0.01 grams per coulomb, and you pass 10 coulombs of charge through the electrolyte, then:
\[
m = E \cdot Q = 0.01 \, \text{g/C} \cdot 10 \, \text{C} = 0.1 \, \text{g}
\]
Thus, 0.1 grams of metal will be deposited.
In summary, the electrochemical equivalent provides a direct way to link the mass of a substance altered during electrolysis with the quantity of charge used, making it a crucial concept in electrochemistry and practical applications like electroplating and battery technology.
Here’s a breakdown of the concept:
### Faraday’s Laws of Electrolysis
1. **First Law**: The mass of a substance altered at an electrode during electrolysis is directly proportional to the quantity of electric charge passed through the electrolyte.
Mathematically:
\[
m = k \cdot Q
\]
where \( m \) is the mass of the substance altered, \( Q \) is the electric charge, and \( k \) is a proportionality constant.
2. **Second Law**: The mass of a substance altered at an electrode during electrolysis is proportional to its equivalent weight and the quantity of electric charge passed through the electrolyte.
### Electrochemical Equivalent
The electrochemical equivalent (E) of a substance is the mass of the substance deposited or dissolved when an electric charge of 1 coulomb passes through the electrolyte. It is a measure that connects the amount of substance changed to the amount of electric charge used.
The relationship can be expressed as:
\[
E = \frac{m}{Q}
\]
where \( E \) is the electrochemical equivalent, \( m \) is the mass of the substance deposited or dissolved, and \( Q \) is the quantity of electric charge.
### Calculating Electrochemical Equivalent
To calculate the electrochemical equivalent of a substance, you use Faraday’s law, considering the molar mass (M) of the substance and the number of electrons (n) involved in the electrochemical reaction. The formula is:
\[
E = \frac{M}{n \cdot F}
\]
where:
- \( M \) is the molar mass of the substance.
- \( n \) is the number of electrons involved in the reaction.
- \( F \) is Faraday's constant (approximately 96485 C/mol).
### Practical Example
For instance, in electroplating, if you know the electrochemical equivalent of the metal being deposited, you can calculate how much metal will be deposited for a given charge. If the electrochemical equivalent of a metal is known to be 0.01 grams per coulomb, and you pass 10 coulombs of charge through the electrolyte, then:
\[
m = E \cdot Q = 0.01 \, \text{g/C} \cdot 10 \, \text{C} = 0.1 \, \text{g}
\]
Thus, 0.1 grams of metal will be deposited.
In summary, the electrochemical equivalent provides a direct way to link the mass of a substance altered during electrolysis with the quantity of charge used, making it a crucial concept in electrochemistry and practical applications like electroplating and battery technology.
Faraday's laws of electrolysis describe the relationship between the amount of substance transformed at an electrode and the quantity of electric charge passed through the electrolyte. The electrochemical equivalent is a concept within Faraday's laws that provides a practical way to relate these quantities. Let's break it down:
### Faraday's Laws of Electrolysis
**First Law**: The amount of a substance transformed at an electrode during electrolysis is directly proportional to the total electric charge passed through the electrolyte. Mathematically, this can be expressed as:
\[ m = kQ \]
where \( m \) is the mass of the substance transformed, \( Q \) is the total charge, and \( k \) is a constant of proportionality.
**Second Law**: The amounts of different substances transformed by the same quantity of electricity are proportional to their equivalent weights. This implies that for a given charge, the mass of different substances transformed is related to their respective equivalent weights.
### Electrochemical Equivalent
The **electrochemical equivalent (E)** of a substance is a specific constant that helps quantify the relationship between the amount of substance transformed and the charge passed through the electrolyte. It can be thought of as the mass of a substance that is deposited or liberated per unit charge (in coulombs) passing through the electrolyte.
**Mathematically**, it is defined as:
\[ E = \frac{m}{Q} \]
where:
- \( E \) is the electrochemical equivalent,
- \( m \) is the mass of the substance deposited or liberated,
- \( Q \) is the electric charge in coulombs.
### Relation to Faraday's Laws
The electrochemical equivalent can be derived from Faraday's laws. For a given substance, the electrochemical equivalent is related to its equivalent weight (Eₑ) and Faraday's constant (F), which is the charge of one mole of electrons (approximately 96485 C/mol).
The electrochemical equivalent \( E \) can be expressed as:
\[ E = \frac{Eₑ}{F} \]
where:
- \( Eₑ \) is the equivalent weight of the substance,
- \( F \) is Faraday's constant.
**Equivalent Weight** of a substance is the mass that will combine with or displace one mole of hydrogen ions or electrons. For example, for a metal ion \( M^n+ \), the equivalent weight is given by:
\[ Eₑ = \frac{M}{n} \]
where \( M \) is the molar mass of the metal and \( n \) is the valency or number of electrons transferred per ion.
### Example
For instance, if you are electrolyzing copper (Cu²⁺), the electrochemical equivalent \( E \) can be calculated knowing the equivalent weight of copper and Faraday's constant. Copper has a molar mass of approximately 63.5 g/mol and it has a valency of 2 (Cu²⁺), so its equivalent weight is:
\[ Eₑ = \frac{63.5}{2} = 31.75 \text{ g/equiv} \]
Given Faraday's constant \( F \approx 96485 \text{ C/mol} \), the electrochemical equivalent \( E \) would be:
\[ E = \frac{31.75}{96485} \approx 0.000329 \text{ g/C} \]
This means that approximately 0.000329 grams of copper will be deposited per coulomb of charge passed through the electrolyte.
### Summary
The electrochemical equivalent provides a direct way to connect the amount of material transformed during electrolysis with the amount of electrical charge used. It simplifies calculations and predictions in electrolysis processes by giving a tangible measure of how much of a substance will be deposited or liberated for a given quantity of electricity.
### Faraday's Laws of Electrolysis
**First Law**: The amount of a substance transformed at an electrode during electrolysis is directly proportional to the total electric charge passed through the electrolyte. Mathematically, this can be expressed as:
\[ m = kQ \]
where \( m \) is the mass of the substance transformed, \( Q \) is the total charge, and \( k \) is a constant of proportionality.
**Second Law**: The amounts of different substances transformed by the same quantity of electricity are proportional to their equivalent weights. This implies that for a given charge, the mass of different substances transformed is related to their respective equivalent weights.
### Electrochemical Equivalent
The **electrochemical equivalent (E)** of a substance is a specific constant that helps quantify the relationship between the amount of substance transformed and the charge passed through the electrolyte. It can be thought of as the mass of a substance that is deposited or liberated per unit charge (in coulombs) passing through the electrolyte.
**Mathematically**, it is defined as:
\[ E = \frac{m}{Q} \]
where:
- \( E \) is the electrochemical equivalent,
- \( m \) is the mass of the substance deposited or liberated,
- \( Q \) is the electric charge in coulombs.
### Relation to Faraday's Laws
The electrochemical equivalent can be derived from Faraday's laws. For a given substance, the electrochemical equivalent is related to its equivalent weight (Eₑ) and Faraday's constant (F), which is the charge of one mole of electrons (approximately 96485 C/mol).
The electrochemical equivalent \( E \) can be expressed as:
\[ E = \frac{Eₑ}{F} \]
where:
- \( Eₑ \) is the equivalent weight of the substance,
- \( F \) is Faraday's constant.
**Equivalent Weight** of a substance is the mass that will combine with or displace one mole of hydrogen ions or electrons. For example, for a metal ion \( M^n+ \), the equivalent weight is given by:
\[ Eₑ = \frac{M}{n} \]
where \( M \) is the molar mass of the metal and \( n \) is the valency or number of electrons transferred per ion.
### Example
For instance, if you are electrolyzing copper (Cu²⁺), the electrochemical equivalent \( E \) can be calculated knowing the equivalent weight of copper and Faraday's constant. Copper has a molar mass of approximately 63.5 g/mol and it has a valency of 2 (Cu²⁺), so its equivalent weight is:
\[ Eₑ = \frac{63.5}{2} = 31.75 \text{ g/equiv} \]
Given Faraday's constant \( F \approx 96485 \text{ C/mol} \), the electrochemical equivalent \( E \) would be:
\[ E = \frac{31.75}{96485} \approx 0.000329 \text{ g/C} \]
This means that approximately 0.000329 grams of copper will be deposited per coulomb of charge passed through the electrolyte.
### Summary
The electrochemical equivalent provides a direct way to connect the amount of material transformed during electrolysis with the amount of electrical charge used. It simplifies calculations and predictions in electrolysis processes by giving a tangible measure of how much of a substance will be deposited or liberated for a given quantity of electricity.