Studied by 3 peopleElectrometallurgy
________- processes that used to produce or refine metals are based on electrolysis.
Sacrificial Anode
________- the metal that is oxidized while protecting the cathode.
Voltaic Cell
________- a device in which the transfer of electrons takes place through an external pathway rather than directly between reactants present in the same reaction vessel.
free energy change
The relationship between emf and the ________ is ∆G=- nFE.
Objects
________ made of iron are often covered with a coat of paint or another metal to protect against corrosion.
stoichiometric coefficient
Changing the ________ in a half- reaction does not affect the value of the standard reduction potential.
Cathode
________- the electrode at which reduction occurs.
Anode
________- the electrode at which oxidation occurs.
Gibbs
The change in the ________ free energy, ∆G, is a measure of the spontaneity of a process that occurs at constant temperature and pressure.
electrolytic cell
A(n) ________ consists of two electrodes immersed either in a molten salt or in a solution.
Battery
________- is a portable, self- contained electrochemical power source that consists of one or more voltaic cells.
emf
The ________, E, of a redox reaction also indicates whether the reaction is spontaneous.
Faraday constant
________ is the quantity of electrical charge on 1 mol of electrons.
Electrons
________ can move through the metal from a region where oxidation occurs to a region where reduction occurs, as in voltaic cells.
mixture of MnO2
The cathode is a(n) ________ (s) and graphite, separated from the anode by a porous fabric.
Electrolysis reactions
________- processes driven by an outside source of electrical energy and takes place in electrolytic cells.
Electrodes
________- the two solid metals connected by the external circuit.
Li ion battery
A(n) ________ produces a maximum voltage of 3.7 V per cell, nearly three times higher than the 1.3 V per cell that nickel- cadmium and nickel- metal hydride batteries generate.
quantity Q
The ________ is the reaction quotient, which has the form of the equilibrium- constant expression except that the concentrations are those that exist in the reaction mixture at a given moment.
corrosion process
The ________ involves oxidation and reduction, and the metal conducts electricity.
Electromotive Force
________ (EMF)- the potential difference provides the driving force that pushes electrons through the external circuit.
Corrosion reactions
________- are spontaneous redox reactions in which a metal is attacked by some substance in its environment and converted to an unwanted compound.
positive value of E
A(n) ________ and a negative value of ∆G both indicate a spontaneous reaction.
Primary Cells
________- batteries that can not be recharged and must be either discarded or recycled after the voltage drops to zero.
thermal energy
The ________ released by burning fuels can be converted to electrical energy.
half reaction
Multiply ________ by integers as needed to make the number of electrons lost in the oxidation ________ equal the number of electrons gained in the reduction ________.
Alkaline Battery
________: The anode is powdered zinc metal immobilized in a gel in contact with a concentrated solution of KOH.
energy change
The free- ________ for any chemical reaction, ∆G, is related to the standard free- energy change for the reaction, ∆G°:
electrolytic cell
The electrodes in a(n) ________ can be inert or active, meaning that the electrode can be involved in the electrolysis reaction.
Half Reactions
________- equations that show either oxidation or reduction alone.
Oxidizing Agent
the substance that oxidizes another substance; also known as oxidant
Law of Conservation of Mass
The amount of each element must be the same on both sides of the equation
Half Reactions
equations that show either oxidation or reduction alone
Voltaic Cell
a device in which the transfer of electrons takes place through an external pathway rather than directly between reactants present in the same reaction vessel
Electrodes
the two solid metals connected by the external circuit
Anode
the electrode at which oxidation occurs
Potential Difference
the difference in potential energy per electrical charge between two electrodes is measured in volts
Cell Potential
the potential difference between the two electrodes of a voltaic cell
Electromotive Force (EMF)
the potential difference provides the driving force that pushes electrons through the external circuit
Standard Cell Potential (Standard EMF)
the cell potential under standard conditions
Standard Reduction Potentials
standard half-cell potentials are tabulated for the reduction reaction
Standard Hydrogen Electrode
an electrode designed to produce this half-reaction
Concentration cell
a cell based solely on the emf generated because of a difference in a concentration
Battery
is a portable, self-contained electrochemical power source that consists of one or more voltaic cells
Primary Cells
batteries that cannot be recharged and must be either discarded or recycled after the voltage drops to zero
Secondary Cells
batteries that can be recharged from an external power source after its voltage has dropped
Alkaline Battery
The anode is powdered zinc metal immobilized in a gel in contact with a concentrated solution of KOH
Nickel-Cadmium Battery
During discharge, cadmium metal is oxidized at the anode while nickel oxyhydroxide is reduced at the cathode
Lithium-Ion Battery
Mostly used in portable electronic devices, including cellphones, and laptop computers
Fuel Cells
voltaic cells that perform high rate of conversion of chemical energy to electricity using conventional fuels
Corrosion reactions
are spontaneous redox reactions in which a metal is attacked by some substance in its environment and converted to an unwanted compound
Cathodic Protection
protecting metal from corrosion by making it the cathode in an electrochemical cell
Sacrificial Anode
the metal that is oxidized while protecting the cathode
Electrolysis reactions
processes driven by an outside source of electrical energy and takes place in electrolytic cells
Electroplating
uses electrolysis to deposit a thin layer of one metal on another metal to improve beauty or resistance to corrosion
Note
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