CHEM-C 127 Lecture Notes - Lecture 3: Electrolytic Cell, Electrical Energy, Electrochemistry
Lab: Electrochemistry
o is the field of chemistry that gives way to many of the products that we use in day to day
life
o such as batteries.
o there are two important cell models
o commonly known as voltaic and electrolytic cells.
o Specifically, batteries are powered by voltaic cells
▪ spontaneous reactions that operate though an outside circuit.
o Electrolytic cell
▪ Electrical energy
• gives us the electricity that we use everyday
• are non-spontaneous
• needs electrical energy to function.
• electric energy is supplied by an outside source
• the reaction will not occur without this input of energy.
o cathode of an electrolytic cell is negative
▪ positive in a voltaic cell.
o anode of an electrolytic cell is positive in an electrolytic cell
▪ negative in a voltaic cell.
o chemical energy is converted to electrical energy in voltaic cells
o electrical energy is converted to chemical energy in electrolytic cells.
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Oxidation and reduction reactions
o also known as redox reactions
o characterized by the transfer of electrons between 2 species
o species that loses electrons is oxidized
o the cell that gains electrons is reduced.
o Both types of cells are composed of half cells
o so that there is a half for reduction and oxidation.
o The flow of electrons can be manipulated
o by reversing the system.
o the reduction will always take place at the cathode, and oxidation will always
occur at the anode.
o Ex: analyzation of the redox reactions that occur between lead, zinc, and copper.
o By manipulating the connections between the cathode, anode
o the metals attached to them
o rhe ideal combination of metals
▪ find the connection that produces the most positive value
o the effect of temperature on the free energy, enthalpy, and entropy of
redox reactions
▪ when each metal was reacted with copper, took the role of
oxidization.
• when copper was connected to the cathode
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