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Voltaic Cell

 
1.3 Voltaic Cell
 
Simple Chemical Cell
  • Two different metal plates are dipped into an electrolyte and connected with connecting wires.
  • Also known as voltaic cell or galvanic cell.
  • Converts chemical energy to electrical energy
  • A redox reaction occurs in the cell that causes the fow of electrons.
  • The potential difference detected by the voltmeter indicates the presence of electrical current
 

 

 
Redox Reaction in a Voltaic Cell
  • The diagram below shows shows an example of a simple chemical cell for a pair of Zn/Cu metals.

This image shows a diagram of a galvanic cell. It includes: - A zinc plate and a copper plate, each connected to a galvanometer. - The zinc plate is submerged in a solution labeled ‘Zinc (II) sulphate solution.’ - The copper plate is submerged in a solution labeled ‘Copper (II) sulphate solution.’ - Both solutions are contained within a porous pot
 

 

 
  • The Eº value of zinc is more negative, therefore, zinc becomes the negative terminal.
  • The reaction that occurs at the negative terminal is oxidation.
  • The Eº value of copper, Cu is more positive; therefore, copper, Cu becomes the positive terminal.

The image is a flowchart titled ‘LESS ELECTROPOSITIVE METAL’ with the following steps: 1. Positive terminal 2. Reduction 3. Receive of an electron 4. Decrease of oxidation number Each step is represented in a box with a number and an arrow pointing to the next step. The background is white, and the text is in blue. The logo ‘Pandai’ is present in the top right corner.
 

 

 

 

This image is an infographic titled ‘More Electropositive Metal.’ It features a four-step process: 1. Negative terminal 2. Oxidation 3. Release of electron 4. Increase of oxidation number Each step is represented by a rectangular box with arrows indicating the sequence from one step to the next. The boxes have a blue and red color scheme, and the logo ‘Pandai’ is present at the top right corner.

  • The reaction at the positive terminal is reduction reaction.
Terminal Half Equation
Negative \(Zn (s) \rightarrow Zn^{2+} (aq) + 2e^-\)
Positive \(Cu^{2+} (aq) + 2e^-\rightarrow Cu(s)\)
  • Electrons flow from the negative terminal to the positive terminal; while the current flows from the positive terminal to the negative terminal.
  • Anode are electrodes where oxidation occurs. In a voltaic cell, the negative terminal is also known as anode.
  • Cathodes are electrodes where reduction occurs. In a voltaic cell, the positive terminal is also known as cathode.
 

 

 

 

 

 

 

The views expressed in the notes here are those of the contributor and don’t necessarily represent the views of Pandai.
Chapter : Redox Equilibrium
Topic : Voltaic Cell
Form 5 Chemistry
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