Electrochemistry
- Electrolytic Refining Of Aluminum
Aluminum is present in most rocks and is the most abundant metallic element in the earth's crust (eight percent by weight.) However, its isolation is very difficult and expensive to accomplish...
- Electrolysis.
Electrolysis refers to the decomposition of a substance by an electric current. The electrolysis of sodium and potassium hydroxides, first carried out in 1808 by Sir Humphrey Davey, led to the discovery of these two metallic elements...
- Galvanic Cells
This arrangement is called a Galvanic cell. A typical cell might consist of two pieces of metal, one zinc and the other copper, each immersed each in a solution containing a dissolved salt of the corresponding metal. The two...
- Electrochemistry
Learning Objectives(a) describe and explain redox processes in terms of electron transfer and/or of changes in oxidation number (oxidation state) (b) define the terms: (i) standard electrode (redox) potential (ii)...
- Electrochemistry : 10.3 : Electrolysis Cell
VOLTAN CELL VS ELECTRIOLYSIS CELL . Voltaic cell :use a spontaneous reaction to generate electric energy. Electrolysis :use electric energy to drive non- spontaneous energy. VOLTAIC CELL. ELECTROLYTICelectrons generate...
Electrochemistry
Faraday's laws of electrolysis.
One mole of electric charge (96,500 coulombs), when passed through a cell, will discharge half a mole of a divalent metal ion such as Cu2+. This relation was first formulated by Faraday in 1832 in the form of two laws of electrolysis:
- The weights of substances formed at an electrode during electrolysis are directly proportional to the quantity of electricity that passes through the electrolyte.
- The weights of different substances formed by the passage of the same quantity of electricity are proportional to the equivalent weight of each substance.
Most stoichiometric problems involving electrolysis can be solved without explicit use of Faraday's laws. The "chemistry" in these problems is usually very elementary; the major difficulties usually stem from unfamiliarity with the basic electrical units:The equivalent weight of a substance is defined as the molar mass, divided by the number of electrons required to oxidize or reduce each unit of the substance. Thus one mole of V3+ corresponds to three equivalents of this species, and will require three faradays of charge to deposit it as metallic vanadium.
- current (amperes) is the rate of charge transport; 1 amp = 1 c/sec.
- power (watts) is the rate of energy production or consumption;
1 w = 1 J/sec = 1 volt-amp; 1 watt-sec = 1 J, 1 kw-h = 3600 J.
- Electrolytic Refining Of Aluminum
Aluminum is present in most rocks and is the most abundant metallic element in the earth's crust (eight percent by weight.) However, its isolation is very difficult and expensive to accomplish...
- Electrolysis.
Electrolysis refers to the decomposition of a substance by an electric current. The electrolysis of sodium and potassium hydroxides, first carried out in 1808 by Sir Humphrey Davey, led to the discovery of these two metallic elements...
- Galvanic Cells
This arrangement is called a Galvanic cell. A typical cell might consist of two pieces of metal, one zinc and the other copper, each immersed each in a solution containing a dissolved salt of the corresponding metal. The two...
- Electrochemistry
Learning Objectives(a) describe and explain redox processes in terms of electron transfer and/or of changes in oxidation number (oxidation state) (b) define the terms: (i) standard electrode (redox) potential (ii)...
- Electrochemistry : 10.3 : Electrolysis Cell
VOLTAN CELL VS ELECTRIOLYSIS CELL . Voltaic cell :use a spontaneous reaction to generate electric energy. Electrolysis :use electric energy to drive non- spontaneous energy. VOLTAIC CELL. ELECTROLYTICelectrons generate...