Ch21_1 - 1 ELECTROCHEMISTRY ELECTROCHEMISTRY Chapter 21 Chapter 21 TRANSFER REACTIONS TRANSFER REACTIONS Atom/Group transfer HCl H 2O> Cl H3O 2 3

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Unformatted text preview: 1 ELECTROCHEMISTRY ELECTROCHEMISTRY Chapter 21 Chapter 21 TRANSFER REACTIONS TRANSFER REACTIONS Atom/Group transfer HCl + H 2O ---> Cl+ H3O+ 2 3 Electron Transfer Reactions Electron Transfer Reactions • Electron transfer reactions are oxidationreduction or redox reactions. • Redox reactions can result in the generation of an electric current or be caused by imposing an electric current. • Therefore, this field of chemistry is often Electron transfer Cu(s) + 2 Ag+(aq) ---> Cu2+(aq) + 2 Ag(s) aq) aq) Ag(s) Electric automobile called ELECTROCHEMISTRY. ELECTROCHEMISTRY. 4 5 6 Review of Terminology Review of Terminology for Redox Reactions for •• OXIDATION—loss of electron(s) by a OXIDATION—loss of electron(s) by a OXIDATION—loss species; increase in oxidation number. species; increase in oxidation number. •• REDUCTION—gain of electron(s); REDUCTION—gain of electron(s); REDUCTION—gain decrease in oxidation number. decrease in oxidation number. •• OXIDIZING AGENT—electron acceptor; OXIDIZING AGENT—electron acceptor; AGENT—electron species is reduced. species is reduced. •• REDUCING AGENT—electron donor; REDUCING AGENT—electron donor; AGENT—electron species is oxidized. species is oxidized. OXIDATION-REDUCTION REACTIONS Direct Redox Reaction Oxidizing and reducing agents in direct contact. Cu(s) + 2 Ag+(aq) ---> Cu2+(aq) + 2 Ag(s) aq) aq) Ag(s) OXIDATION-REDUCTION OXIDATION-REDUCTION REACTIONS REACTIONS Indirect Redox Reaction A battery functions by transferring electrons through an external wire from the reducing agent to the oxidizing agent. Page 1 Why Study Electrochemistry? Why Study Electrochemistry? • Batteries • Corrosion • Industrial production of chemicals such as such Cl2, NaOH, F2 and NaOH, and Al • Biological redox reactions The heme group 7 8 Electrochemical Cells Electrochemical Cells • An apparatus that allows a redox reaction to occur by transferring electrons through an external connector. • Product favored reaction ---> voltaic or galvanic cell ----> electric current • Reactant favored reaction ---> electrolytic cell ---> electric current used to cause chemical change. Batteries are voltaic cells Page 2 ...
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This note was uploaded on 12/14/2010 for the course ECON 1b03 taught by Professor Holmes during the Winter '10 term at Macalester.

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