Chemistry Unit 6 Lesson 1

What are some uses of electrolytic cells?

-Electroplating metal coatings onto jewelry, silverware, and other objects: Electroplating protects metals from corrosion or puts fine coatings of precious metals on objects. -Producing chlorine gas from sodium chloride for disinfecting water: This process has the advantage of using small systems on-site, rather than transporting quantities of toxic chlorine gas from large suppliers.

Metals have a reactivity series with respect to redox reactions.

Chemists have observed which metals will donate electrons and which elements will receive electrons in various spontaneous redox reactions.

Chemical energy can be converted to electrical energy—and vice versa.

Interconversions of chemical energy and electrical energy take place every day.

Electrochemistry produces useful technologies.

Many chemical reactions involve the transfer of electrons from one substance to another. Electrical current is the movement of electrons, and many chemical reactions can produce electrical energy. Electrochemists study the relationship between electrical energy and chemical energy. They develop technologies for producing electricity from chemical reactions and for driving chemical reactions with electrical energy. In this lesson, you will get an overview of electrochemical processes.

In electrochemical cells, oxidation-reduction half-reactions take place in separate compartments connected by solutions and with a separate path for the flow of electrons.

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Many chemical reactions involve the transfer of electrons from one substance to another. The movement of electrons also defines an electrical current. So in one way or another, many chemical reactions can produce electrical energy. Likewise, electrical energy can be used to drive chemical reactions. In this unit, you will examine electrochemical processes—how they can be used to produce electricity and, conversely, how electricity can be used to elicit useful chemical reactions. You will look at the technologies involved in electrochemistry, including voltaic cells, batteries, and electrolytic cells.

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Redox reactions involve the donation and acceptance of electrons.

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Voltaic or galvanic cells use spontaneous redox reactions to produce electricity. Electrolytic cells use electrical energy to drive nonspontaneous redox reactions.

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How can redox reactions produce electricity?

how a voltaic cell or galvanic cell works: -Cd electrode: Cd (s) →Cd2+ (aq) + 2e- -Oxidation occurs. Cd atoms ionize and move from the electrode into the solution. -Electrons move from the solid Cd through the wire and light bulb to the solid Ag (the light shines). -Ag electrode: 2Ag+ (aq) + 2e- →2Ag (s) Reduction occurs. --Metallic Ag produced from the solution accumulates on the solid Ag. -NO3- ions move through the bridge to maintain neutrality.

How can you convert electrical energy to chemical energy?

how an electrolytic cell works: -The battery moves electrons from the Ag strip to the Fe -strip. -Ag electrode: Ag (s) →Ag+ (aq) + e- -Oxidation occurs. The battery removes electrons from Ag atoms, causing them to ionize and move from the strip into the solution. -Fe electrode: Ag+ (aq) + e- →Ag (s) -Reduction occurs. Metallic Ag produced from the solution accumulates on the solid Fe.

What is an electrochemical cell?

interconvert chemical energy and electrical energy, depending on the type. They have these features in common: -They use metals strips as electrodes. -The strips are either in the same solution or in separate -solutions that are connected. -Oxidation-reduction half-reactions occur at each electrode. -A wire allows the flow of electrons. -Ions flow through the solutions to maintain neutrality. -Electrochemical cells can be divided into two types: Voltaic (galvanic) cell: A spontaneous redox reaction creates electricity. Electrolytic cell: Electricity drives a nonspontaneous redox reaction (electroplating).

The basis for electrochemistry is a redox reaction.

redox: a term that is used as shorthand for oxidation-reduction reactions

Oxidation

the process in which a substance gains oxygen, or more comprehensively, loses electrons, during a chemical reaction

Reduction

the process in which a substance loses oxygen, or more comprehensively, gains electrons, during a chemical reaction

Electrochemistry

the study of the interaction of chemical reactions and electricity