CHEM 114: Foundation Chemistry II Flashcards

These vocabulary flashcards cover the fundamental definitions, purification techniques, analytical methods, and structural concepts of CHEM 114 Foundation Chemistry II.

Organic Chemistry

The scientific study of carbon-containing compounds and the reactions they undergo, with specific exceptions like $Na_2CO_3$, $KCN$, and $CO_2$.

Catenation

The unique ability of Group 4 elements, such as carbon, silicon, germanium, tin, and lead, to form stable chains with atoms of the same element.

Tetrahedral Geometry

The molecular shape occurring when four atoms or groups are attached to a carbon atom, characterized by a bond angle of $109.5^\text{\textdegree}$.

Trigonal Planar Geometry

The molecular shape occurring when three atoms or groups are attached to a carbon atom, characterized by a bond angle of $120^\text{\textdegree}$.

Linear Geometry

The molecular shape occurring when two atoms or groups are attached to a carbon atom, characterized by a bond angle of $180^\text{\textdegree}$.

Macromolecule

A large organic compound formed from many small, similar molecules polymerized into a chain structure, such as proteins, carbohydrates, and nucleic acids.

Metabolism

The cellular process of breaking down or building up macromolecules; breaking down releases energy while building up requires energy.

Melting Point of Pure Solid

A physical property where a solid melts reproducibly over a narrow temperature range, typically less than $1^\text{\textdegree}C$.

Boiling Point

The temperature at which the vapor pressure of a liquid is equal to the atmospheric pressure.

Refractive Index ($n$)

A wave-dependent physical constant representing the ratio of the velocity of light in a vacuum to the velocity of light in a sample: $n = \frac{\text{velocity in vacuum}}{\text{velocity in sample}}$.

Thin Layer Chromatography (TLC)

An analytical technique involving a stationary phase (Silica or Alumina) and a mobile phase (Solvents) that ascends the stationary phase to separate organic compounds.

$R_f$ Value

A measure of the distance travelled by a substance relative to the distance travelled by the solvent, calculated as: $R_f = \frac{\text{distance travelled by substance}}{\text{distance travelled by solvent}}$.

Simple Distillation

A purification technique effective for separating liquid mixtures when the boiling points of the components differ significantly, usually by more than $30^\text{\textdegree}C$ to $40^\text{\textdegree}C$.

Fractional Distillation

A distillation process used for mixtures with close boiling points ($< 30^\text{\textdegree}C \text{--} 40^\text{\textdegree}C$), employing a fractionating column to provide surface area for repeated vaporization and condensation.

Vacuum Distillation

A method used for air-sensitive or high-boiling compounds that might decompose, where decreased pressure lowers the boiling point of the substances.

Steam Distillation

A process used for heat-sensitive compounds that are nearly immiscible with water, where steam carries the vapor of the substances at an overall lower boiling point for the mixture.

Recrystallization

A purification method for solids where a compound is dissolved in a solvent at high temperatures and then precipitates as pure crystals as the solution cools.

Sublimation

The physical process in which a substance interconverts between the solid and gaseous states without passing through the liquid phase.

Partition Coefficient ($K$)

A constant defining the relative amounts of a compound in two immiscible liquid phases at equilibrium, expressed as $K = C_o/C_w$.

Sodium Fusion Test (Lassaigne Test)

A quantitative analysis procedure where an organic compound is heated with sodium to convert elements like Nitrogen, Sulfur, and Halogens into water-soluble sodium salts.

Empirical Formula

The chemical formula showing the smallest whole-number mole ratio of the elements present in a compound.

Molecular Formula

A chemical formula that specifies the actual number of atoms of each element present in a single molecule of a substance.

Infrared (IR) Spectroscopy

A technique used to identify functional groups in organic compounds by measuring the absorption of radiation that causes molecular bonds to vibrate.

Ultra-violet (UV) Spectroscopy

A spectroscopic method used to detect the presence of conjugated $\pi$-bonded systems by measuring transitions of electrons to higher energy orbitals.

Nuclear Magnetic Resonance (NMR) Spectroscopy

A diagnostic technique that maps the magnetic environment of atoms like $^1H$ (protons) and $^{13}C$ to determine the structural framework of a molecule.

Mass Spectrometry (MS)

A method used to determine the molecular weight and fragmentation pattern of a compound by ionizing molecules and separating them according to their mass-to-charge ($m/z$) ratio.

Hybridization

The mixing of atomic orbitals (such as $s$ and $p$) to form new, equivalent hybrid orbitals designed to minimize the bonding energy of the molecule.

Sigma (\sigma) Bond

A covalent bond formed by the end-to-end overlap of atomic orbitals, with the electron density concentrated along the internuclear axis.

Pi (\pi) Bond

A covalent bond formed by the sideways overlap of $p$-orbitals, where the electron density is located above and below the plane of the internuclear axis.

Constitutional Isomers

Compounds that share the same molecular formula but differ in the connectivity or sequence of their atoms.

Stereoisomers

Isomers with the same connectivity and molecular formula but a different arrangement of their atoms in three-dimensional space.

Conformational Isomers

Stereoisomers that represent different temporary shapes of a molecule resulting from rotation around single carbon-carbon bonds.

Chiral

A property of molecules that are nonsuperposable on their mirror images, similar to the handedness of gloves or shoes.

Enantiomers

A pair of stereoisomers that are nonsuperposable mirror images of each other.

Diastereomers

Stereoisomers that are not mirror images of each other, such as cis and trans isomers.

Specific Rotation ([\alpha])

A physical constant for chiral substances calculated as $[\alpha] = \frac{\alpha}{c \times l}$, where $\alpha$ is observed rotation, $c$ is concentration in $g/mL$, and $l$ is path length in $dm$.

Racemic Mixture

An equimolar mixture of two enantiomers that shows no net rotation of plane-polarized light and is deemed optically inactive.

Degree of Unsaturation

The total number of multiple bonds or rings in a molecule, calculated as: $\frac{2C + 2 + N - X - H}{2}$.

Markovnikov's Rule

The principle stating that in the addition of $HX$ to an unsymmetrical alkene, the hydrogen attaches to the carbon with more hydrogen atoms to yield the more stable carbocation intermediate.

Zaitsev Rule

A rule stating that elimination reactions favor the formation of the more stable, more highly substituted alkene product.

Tautomers

Isomers that rapidly interconvert through the migration of a proton and a double bond, such as the keto and enol forms of a carbonyl compound.