Analytical and Organic Chemistry Practice Flashcards

Flashcards covering chemical analysis methods (Kjeldahl, potentiometry, spectroscopy), electrochemistry, thermodynamics, nuclear chemistry, and organic polymerization.

Kjeldahl method

An analytical method used to determine the nitrogen content of a sample by liberating ammonia ($NH_3$) and performing a back-titration of the collected acid.

Potentiometry

The branch of electrochemistry concerned with the relationship between the potential of an electrochemical cell and the concentration of the contents of the cell.

Reference electrode

A half-cell having a known electrode potential that remains constant at constant temperature and is independent of the composition of the analyte solution.

Z (Ionic Strength Formula)

In the formula for determining ionic strength, this variable represents the charge of the ion.

Charge balance equation for $Ag_3AsO_4$

The equation representing electrical neutrality: $[Ag^{+}] + [H^{+}] = 3[AsO_4^{3-}] + 2[HAsO_4^{2-}] + [H_2AsO_4^{-}] + [OH^{-}]$.

Electrogravimetry

The electrochemical method that requires the formation of an insoluble form of the analyte on an electrode.

Oxidizing agent

The species that gains electrons in a redox reaction, such as $Cu^{2+}(aq)$ in the cell: $Zn(s) | Zn^{2+}(aq) || Cu^{2+}(aq) | Cu(s)$.

Limiting current

In a linear sweep voltammogram, this value is related to the concentration of the analyte of interest.

Connes advantage

The frequency accuracy advantage in infrared spectroscopy where the instrument is capable of self-calibration.

Internal conversion

A process where a molecule moves from an excited electronic state ($S_1$) to a highly excited vibrational level of the ground state ($S_0$) with the same energy after absorbing a photon.

Transmittance ($T$)

The ratio of the radiant power transmitted by the sample ($P$) to the radiant power incident on the sample ($P_0$).

Internal standard

A substance chemically similar to the analyte added to all samples during measurement; its physical properties must be close to the analyte, and it does not exhibit zero signal.

Inclusion

A co-precipitated impurity in which the interfering ion occupies a lattice site in the crystal precipitate.

Addition polymerization

A process where monomers are added to form a chain without creating other byproduct products.

Condensation polymerization

A process where small molecules react to form larger structural units while releasing smaller molecules as a byproduct.

Anode

The electrode at which oxidation occurs in a Galvanic cell.

Peptide

A natural polymer made up of 2 up to 50 amino acids.

Technical reagents

Reagents that have undergone superficial purification and are seldom used in analytical work.

Mass deficiency

The difference in mass between the individual nucleons of an atom and the actual atomic mass (e.g., $0.6002\,g/mol$ for Zinc-64).

Nuclear chain reaction

A self-sustaining series of nuclear fissions caused by the absorption of neutrons released from previous nuclear fissions.

Radioactive Half-life

The period of time independent of the amount of the sample that describes the rate of radioactive decay, following first-order kinetics.

Equimolar Buffer Solution

A buffer condition where the concentration of the acid and conjugate base components are equal, making the pH of the solution equal to the $pKa$ of the acid component.