Chapter 21 Flashcards
ampere (A)
the SI unit of electric current; 1 ampere of current results when 1 coulomb of charge flows through a conductor in 1 second
anode
the electrode at which oxidation occurs in an electrochemical cell. Electrons are given up by the reducing agent and leave the cell at the anode
battery
a group of voltaic cells arranged in series; primary and secondary types are self-contained, but flow batteries are not
cathode
the electrode at which reduction occurs in an electrochemical cell. Electrons enter the cell and are acquired by the oxidizing agent at the cathode
cell potential/voltage
the difference in electrical potential between the two electrodes of an electrochemical cell
concentration cell
a voltaic cell in which both compartments contain the same components but at different concentrations
corrosion
the natural redox process that results in unwanted oxidation of a metal
coulomb (C)
the SI unit of electric charge. One coulomb is the charge of 6.242 × 1018 electrons; one electron possesses a charge of 1.602 × 10−19 C
electrochemical cell
a system that incorporates a redox reaction to produce or use electrical energy
electrochemistry
the study of the relationship between chemical change and electrical work
electrode
the part of an electrochemical cell that conducts the electricity between the cell and the surroundings
electrolysis
the nonspontaneous lysing (splitting) of a substance, often to its component elements, by the input of electrical energy
electrolyte
a mixture of ions, in which the electrodes of an electrochemical cell are immersed, that conducts a current
electrolytic cell/electromotive force (emf)
an electrochemical system that uses electrical energy to drive a nonspontaneous chemical reaction (ΔG > 0)
Faraday constant (F)
the physical constant representing the charge of 1 mol of electrons: F = 96,485 C/mol e−
fuel cell
a battery that is not self-contained and in which electricity is generated by the controlled oxidation of a fuel
half-cell
a portion of an electrochemical cell in which a half-reaction takes place
half-reaction method
a method of balancing redox reactions by treating the oxidation and reduction half-reactions separately
Nernst equation
an equation stating that the voltage of an electrochemical cell under any conditions depends on the standard cell voltage and the concentrations of the cell components
overvoltage
the additional voltage, usually associated with gaseous products forming at an electrode, that is required above the standard cell voltage to accomplish electrolysis
salt bridge
an inverted U tube containing a solution of nonreacting ions that connects the compartments of a voltaic cell and maintains neutrality by allowing ions to flow between compartments
standard cell potential
the potential of a cell measured with all components in their standard states and no current flowing
standard electrode potential
the standard potential of a half-cell, with the half-reaction written as a reduction
standard reference half-cell (SHE)
specially prepared platinum electrode immersed in 1 M H+(aq) through which H2 gas at 1 atm is bubbled. E half cell is defined as 0 V
