Quantitative aspects of electrolysis

The stoichiometry of a half-reaction shows how many electrons are needed to achieve an electrolytic process. For example, the reduction of Na to Na is a one-electron process  

For any half-reaction, the amount of substance reduced or oxidized in an electrolytic cell is directly proportional to the number of electrons passed into the cell. 

EXERCISE 20.14 Relating Electrical Charge and Quantity of Electrolysis 

Calculate the number of grams of aluminum produced in 1.00 h by the electrolysis of molten AICI3 if the electrical current is 10.0 A. 

When Zn electrodes dip into ZnS04 solution, Zn(s) goes into solution at the anode and Zn(s) is deposited at the cathode and the reactions occurring are  

Carry out the same sort of analysis as given above in Section 9.2.1 for reaction 2 of Worked Problem 9.1. 

In this case the number of electrons have to be the same, and so the cathode reaction will have to be written as  

An alternative procedure would be to halve the initial reaction occurring at the anode giving for the electrode reactions  

It is immaterial which stoichiometry is used, provided everything is internally self consistent. 

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The Quantitative Aspects of Electrolysis activity in eChapter 18.13 walks you through the steps for calculating the mass of metal that can be produced by an electrolytic cell for a given time at a certain current. Write down each of the steps required for the problem given then use a similar procedure to determine the mass of copper that can be produced by passing a current of 18.0 A through a solution of copper(II) ions for 1.0 hour. 

In electrolysis cells, chemical reactions are produced by electric currents. (Section 17.4) Quantitative aspects of electrolysis reactions are presented in Section 17.5. 

This chapter explains the fundamental principles and applications of electrochemical cells, the thermodynamics OF electrochemical reactions, and the cause and prevention of corrosion BY ELECTROCHEMICAL MEANS. SOME SIMPLE ELECTROLYTIC processes and the QUANTITATIVE ASPECTS OF ELECTROLYSIS ARE ALSO discussed. 

In contrast to spontaneous redox reactions, which result in the conversion of chemical energy into electrical energy, electrolysis is the process in which electrical energy is used to cause a nonspontaneous chemical reaction to occur. An electrolytic cell is an apparatus for carrying out electrolysis. The same principles underlie electrolysis and the processes that take place in electrochemical cells. Here we will discuss three examples of electrolysis based on those principles. Then we will look at the quantitative aspects of electrolysis. 

Electrolysis of Molten Sodium Chloride. Electrolysis of Water Electrolysis of an Aqueous Sodium Chloride Solution. Quantitative Aspects of Electrolysis... 

The electrochemistry section (Chapter 20) has been expanded to include basic electrochemical terms and quantitative aspects of electrolysis. 

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