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Chapter 21 - Electrochemistry: Chemical Change and Electrical Work

  • The oxidizing agent oxidizes the material being oxidized by removing electrons from it. The reducing agent reduces the material being reduced by donating electrons to it. As a result, the reducing agent is reduced and the oxidizing agent is oxidized.

  • The oxidized material has a greater (more positive or less negative) oxidation number (O.N.), whereas the reduced substance has a lower (less positive or more negative) O.N.

  • The entire number of electrons obtained by the oxidizing agent's atoms/ions matches the total number lost by the reducing agent's atoms/ions. The image attached below depicts the aqueous interaction between zinc metal and H+ from strong acid.

  • The half-reaction technique is particularly useful for understanding electrochemistry because it splits the entire redox reaction into oxidation and reduction half-reactions, which, as you will see, represent their physical separation in electrochemical cells.

  • It is highly suited to reactions in acidic or basic solutions, which are prevalent in cells. It (generally) does not necessitate the assignment of O.N.s. (In instances where the half-reactions are present.) Not surprisingly, we assign O.N.s to identify which atoms change and which do not. Half-reactions with the species containing those atoms should be written.)

  • The basic distinction between the two types of electrochemical cells is whether the cell's overall redox reaction is spontaneous (free energy is released) or nonspontaneous (free energy is absorbed):

      1. First, we'll look into voltaic cells (also known as galvanic cells):

  • A voltaic cell generates electrical energy by a spontaneous redox reaction (G 0).

  • Some of the difference in free energy between higher energy reactants and lower energy products is transformed into electrical energy in the cell reaction, which powers the load—flashlight, MP3 player, automobile starter motor, and so on.

  • The voltaic cell (the system) works on the environment (load).

  • Then we'll talk about electrolytic cells, which employ electrical energy to drive a nonspontaneous redox reaction (G > 0).

  • An external power source provides free energy to convert in the cell process. Lower energy reactants are converted into higher energy products.

  • The environment (power supply) has an effect on the system (the electrolytic cell). Electrolytic cells are used in electroplating and metal recovery from ores.

  • There are numerous similarities between the two types of cells. Two electrodes, which conduct electricity between the cell and its surroundings, are immersed in an electrolyte, which is a combination of ions (typically in an aqueous solution) that are engaged in the reaction or transport the charge (as shown in the image attached).

  • An electrode is classified as anode or cathode based on the half-reaction that occurs there:

  • The anode is where the oxidation half-reaction takes place. Electrons lost by the oxidizing material (reducing agent) exit the oxidation half-cell at the anode.

  • At the cathode, the reduction half-reaction occurs. Electrons acquired by the material being reduced (oxidizing agent) enter the cathode of the reduction half-cell.

  • It should be noted that, for reasons that will be discussed momentarily, the relative charges of the electrodes are the two sorts of cells that have opposing signs.

  • An oxidation-reduction (redox) process includes the transfer of electrons from a reducing environment to a reducing environment from a reducing agent to an oxidizing agent.

  • The half-reaction technique splits the total response into half-reactions that are balanced. Separately balanced and then recombined.

  • Electrochemical cells are classified into two kinds. A spontaneous reaction creates electricity and works on the surroundings in a voltaic cell.

  • The surroundings give electricity to an electrolytic cell, which does work to cause a nonspontaneous reaction.

  • In both types of cells, two electrodes are immersed in electrolyte solutions; oxidation happens at the electrodes.

  • The anode undergoes reduction, whereas the cathode undergoes reduction.

  • The oxidizing agent oxidizes the material being oxidized by removing electrons from it. The reducing agent reduces the material being reduced by donating electrons to it. As a result, the reducing agent is reduced and the oxidizing agent is oxidized.

  • The oxidized material has a greater (more positive or less negative) oxidation number (O.N.), whereas the reduced substance has a lower (less positive or more negative) O.N.

  • The entire number of electrons obtained by the oxidizing agent's atoms/ions matches the total number lost by the reducing agent's atoms/ions. The image attached below depicts the aqueous interaction between zinc metal and H+ from strong acid.

  • The half-reaction technique is particularly useful for understanding electrochemistry because it splits the entire redox reaction into oxidation and reduction half-reactions, which, as you will see, represent their physical separation in electrochemical cells.

  • It is highly suited to reactions in acidic or basic solutions, which are prevalent in cells. It (generally) does not necessitate the assignment of O.N.s. (In instances where the half-reactions are present.) Not surprisingly, we assign O.N.s to identify which atoms change and which do not. Half-reactions with the species containing those atoms should be written.)

  • The basic distinction between the two types of electrochemical cells is whether the cell's overall redox reaction is spontaneous (free energy is released) or nonspontaneous (free energy is absorbed):

      1. First, we'll look into voltaic cells (also known as galvanic cells):

  • A voltaic cell generates electrical energy by a spontaneous redox reaction (G 0).

  • Some of the difference in free energy between higher energy reactants and lower energy products is transformed into electrical energy in the cell reaction, which powers the load—flashlight, MP3 player, automobile starter motor, and so on.

  • The voltaic cell (the system) works on the environment (load).

  • Then we'll talk about electrolytic cells, which employ electrical energy to drive a nonspontaneous redox reaction (G > 0).

  • An external power source provides free energy to convert in the cell process. Lower energy reactants are converted into higher energy products.

  • The environment (power supply) has an effect on the system (the electrolytic cell). Electrolytic cells are used in electroplating and metal recovery from ores.

  • There are numerous similarities between the two types of cells. Two electrodes, which conduct electricity between the cell and its surroundings, are immersed in an electrolyte, which is a combination of ions (typically in an aqueous solution) that are engaged in the reaction or transport the charge (as shown in the image attached).

  • An electrode is classified as anode or cathode based on the half-reaction that occurs there:

  • The anode is where the oxidation half-reaction takes place. Electrons lost by the oxidizing material (reducing agent) exit the oxidation half-cell at the anode.

  • At the cathode, the reduction half-reaction occurs. Electrons acquired by the material being reduced (oxidizing agent) enter the cathode of the reduction half-cell.

  • It should be noted that, for reasons that will be discussed momentarily, the relative charges of the electrodes are the two sorts of cells that have opposing signs.

  • An oxidation-reduction (redox) process includes the transfer of electrons from a reducing environment to a reducing environment from a reducing agent to an oxidizing agent.

  • The half-reaction technique splits the total response into half-reactions that are balanced. Separately balanced and then recombined.

  • Electrochemical cells are classified into two kinds. A spontaneous reaction creates electricity and works on the surroundings in a voltaic cell.

  • The surroundings give electricity to an electrolytic cell, which does work to cause a nonspontaneous reaction.

  • In both types of cells, two electrodes are immersed in electrolyte solutions; oxidation happens at the electrodes.

  • The anode undergoes reduction, whereas the cathode undergoes reduction.