Electrochemistry Lecture Fundamentals

These flashcards cover the fundamental vocabulary and concepts of electrochemistry, including redox reactions, cell types, potentials, and commercial electrolytic processes based on the lecture notes.

Electrochemistry

The science that unites electricity and chemistry; it is the study of the transfer of electrons.

Electrochemical Reaction

A chemical reaction driven by an external applied voltage, as in electrolysis, or one where a voltage is created by a chemical reaction, as in a battery.

Oxidation

The loss of electrons during a chemical process; it occurs at the anode in an electrochemical cell.

Reduction

The gain of electrons during a chemical process; it occurs at the cathode in an electrochemical cell.

Reducing Agent

The electron donor in a redox reaction that causes reduction in another substance.

Oxidizing Agent

The electron acceptor in a redox reaction that causes oxidation in another substance.

Voltage

The measurement of electric potential difference, expressed in the SI unit volts ($V$).

Electric Charge

That which causes electrons and ions to attract each other and repel particles of the same kind, measured in Coulombs ($C$).

Current

The flow of charge per unit of time, measured in Ampere ($A$), which is equal to $1 \text{ C/s}$.

Joule

A unit of energy where one joule is used when $1 \text{ C}$ moves across a potential of $1 \text{ V}$. Energy ($J$) = potential ($V$) $\times$ Charge ($C$).

Electrolytic Cell

An electrochemical cell in which electrical energy is used to force nonspontaneous chemical reactions to occur.

Voltaic (Galvanic) Cell

An electrochemical cell containing spontaneous chemical reactions that convert chemical energy to electrical energy.

Anode

The electrode where oxidation occurs; it is designated as the negative ($-$) terminal in a galvanic cell.

Cathode

The electrode where reduction occurs; it is designated as the positive ($+$) terminal in a galvanic cell.

Salt Bridge

A component containing a strong electrolyte held in a gel-like matrix that allows ions to flow between cells without extensive mixing.

Porous Disk

A component containing tiny passages that allow the hindered flow of ions to maintain charge balance in a cell.

Metallic Conduction

A process where metals conduct electric currents via electron flow with no atomic motion.

Electrolytic (Ionic) Conduction

A process where ionic motion transports electrons through a medium.

Cell Potential ($E_{cell}$)

The driving force or electromotive force (emf) that allows electrons to flow, measured in Volts ($V$), where $1 \text{ V} = 1 \text{ J/C}$ of charge transferred.

Standard Hydrogen Electrode (SHE)

The arbitrary standard used to measure relative electrode potentials, assigned a voltage of $0.000000 \text{ V}$.

Standard Reduction Potential ($E^\text{o}$)

The voltage associated with a reduction reaction at an electrode when all solutes are $1 \text{ M}$ and all gases are at $1 \text{ atm}$.

Nernst Equation

An equation used to calculate cell potential ($E$) when conditions are nonstandard, defined as $E = E^\text{o} - \frac{RT}{nF} \text{ln}(Q)$.

Faraday Constant ($F$)

A constant used in electrochemical calculations equal to $96,485 \text{ coulombs/mol } e^-$.

Primary Voltaic Cell

A non-rechargeable cell where chemicals are consumed during discharge and cannot be regenerated by reversing current flow.

Secondary Voltaic Cell

A reversible, rechargeable cell where electrodes can be regenerated by the addition of electricity.

Lead Storage Battery

A secondary cell common in cars featuring lead alloy grids, lead (IV) oxide ($PbO_2$), and dilute sulfuric acid ($H_2SO_4$) as the electrolyte.

Fuel Cell

Batteries that require reactants to be continuously supplied in the presence of catalysts, such as the hydrogen-oxygen fuel cell used in space shuttles.

Corrosion

The process involving the oxidation of metal that returns it to its oxidized state.

Cathodic Protection

A method of preventing corrosion by connecting the metal to be protected to a more active metal anode, such as magnesium.

Downs Cell

A specialized electrolytic cell used for the electrolysis of molten sodium chloride ($NaCl$) to produce liquid sodium and gaseous chlorine.

Hall-Heroult Process

A commercial electrolytic process used for the production of aluminum from a molten mixture of $Al_2O_3$ and $Na_3AlF_6$.