Book: Key Terms: Ch. 21 Flashcards
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.
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.
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 (E_cell)
aka electromotive force, or emf; cell 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.
coulomb (C)
The SI unit of electric charge. One coulomb is the charge of 6.242×10^18 electrons; one electron possesses a charge of 1.602×10^-19 C.
corrosion
The natural redox process that results in unwanted oxidation of a metal.
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.
electrolytic cell
An electrochemical system that uses electrical energy to drive a nonspontaneous chemical reaction (∆G > 0).
electrode
The part of an electrochemical cell that conducts the electricity between the cell and the surroundings.
electrolyte
A substance that conducts a current when it dissolves in water. A mixture of ions, in which the electrodes of an electrochemical cell are immersed, that conducts a current.
electromotive force (emf)
aka cell potential. The difference in electrical potential between the two electrodes of an electrochemical cell.
electrolysis
The nonspontaneous lysing (splitting) of a substance, often to its component elements, by the input of electrical energy.
Faraday constant (F)
The physical constant representing the charge of 1 mol of electrons: F = 96485 C / mol e⁻
fuel cell
aka flow battery. A battery that is not self-contained and in which electricity is generated by the controlled oxidation of 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 concentrations of the cell components: E_cell = Eº_cell - ( RT / nF ) ln( Q )
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 the compartments.
standard cell potential (Eº_cell)
The potential of a cell measured with all components in their standard states and no current flowing.
standard electrode (half-cell) potential (Eº_half-cell)
aka standard half-cell potential. The standard potential of a half-cell, with the half-reaction written as a reduction.
standard reference half-cell (standard hydrogen electrode)
aka standard hydrogen electrode. A specially prepared platinum electrode immersed in 1 M H+ (aq) through which H2 gas at 1 atm is bubbled. Eº_half-cell is defined as 0 V.
volt (V)
The SI unit of electric potential: 1 V = 1 J / C.
voltaic (galvanic) cell
an electrochemical cell that uses a spontaneous redox reaction to generate electrical energy.
voltage
aka cell potential. The difference in electrical potential between the two electrodes of an electrochemical cell.
