CHEM114: Compounds of Life, Purification, and Spectroscopy

Vocabulary-style flashcards covering basic organic chemistry concepts, purification methods, elemental analysis, and spectroscopic techniques based on the CHEM114 course.

Organic Chemistry

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

Catenation

The ability of Group 4 elements ($C$, $Si$, $Ge$, $Sn$, $Pb$) to form chains with themselves; this ability decreases down the group.

Tetrahedral Geometry

The geometry of a carbon atom attached to four atoms or groups, characterized by a bond angle of $109.5^{\text{o}}$, such as in Methane ($CH_4$).

Trigonal Planar Geometry

The geometry of a carbon atom attached to three atoms or groups, characterized by a bond angle of $120^{\text{o}}$, such as in Ethene ($C_2H_4$).

Linear Geometry

The geometry of a carbon atom attached to two atoms or groups, characterized by a bond angle of $180^{\text{o}}$, such as in Ethyne ($C_2H_2$).

Formic Acid

The simplest organic acid ($HCOOH$) found in the stings of red ants, bees, and some plants.

Ethylene

The organic gas responsible for ripening fruit.

Macromolecule

A combination of many small but similar molecules polymerized into a chain structure; the three main types are Proteins, Carbohydrates, and Nucleic acids.

Metabolism

The process of breaking down macromolecules (releasing energy) or building them up (requiring energy).

Proteins

Macromolecules that function as polymers of amino acids.

Carbohydrates

Molecular compounds containing carbon, hydrogen, and oxygen; includes sugars like monosaccharides (glucose) and disaccharides (sucrose).

Boiling Point

The temperature at which the vapor pressure of a liquid equals atmospheric pressure; it decreases about $0.5^{\text{o}}C$ for every $10\text{-mm}$ decrease in pressure.

Refractive Index ($n$)

A wave-dependent value greater than 1, defined as the ratio of the velocity of light in a vacuum to the velocity in a sample (n = \frac{\text{sin } \text{\textphi}}{\text{sin } \text{\textphi}_1}).

Thin Layer Chromatography (TLC)

A technique using a stationary phase (Silica or Alumina) and a mobile phase (Solvents) where the mobile phase ascends to separate compounds.

$R_f$ Value

A measure used in chromatography calculated as: $\text{distance travelled by substance} \text{ / } \text{distance travelled by solvent}$.

Simple Distillation

A purification method most effective when the boiling points of liquid samples are widely different, typically by $> 30^{\text{o}}C - 40^{\text{o}}C$.

Fractional Distillation

Used for liquid mixtures with boiling points close together ($< 30^{\text{o}}C - 40^{\text{o}}C$); it utilizes a fractionating column for repeated vaporization-condensation cycles (theoretical plates).

Vacuum Distillation

A method for air-sensitive compounds with high boiling points, where decreasing the pressure lowers the boiling point to prevent decomposition.

Steam Distillation

A technique for heat-sensitive compounds nearly immiscible with water, allowing the mixture to boil below the boiling point of either pure component.

Recrystallization

A purification process where a solid compound is dissolved in a solvent at high temperature and precipitates out as crystals when cooled.

Sublimation

The process where a molecule interconverts between solid and gaseous states without passing through the liquid phase.

Soxhlet Extractor

An instrument used for solid-liquid extraction that recycles small amounts of solvent to extract large amounts of material.

Partition Coefficient ($K$)

The constant defined as the ratio of compound concentrations in two immiscible phases at equilibrium ($K = C_o / C_w$).

Gas Chromatography

Specifically used to separate small quantities of volatile mixtures using carrier gases like Helium or Nitrogen.

High Pressure Liquid Chromatography (HPLC)

A technique using pressure to increase flow rates through small-particle stationary phases, effective for separating and quantifying heat-sensitive analytes.

Lassaigne Test

Also known as the Sodium Fusion Test; it involves heating a compound with sodium to form salts ($NaCN$, $Na_2S$, $NaX$) for elemental detection.

Kjeldahl Method

A quantitative analysis method used to determine the amount of nitrogen in an organic compound.

Empirical Formula

The formula expressing the smallest whole-number mole ratio of elements in a compound.

Molecular Formula

The formula specifying the actual number of atoms of each element in a molecule, calculated as: $(\text{Empirical Formula}) \times n$.

IR Spectroscopy

A method using infrared radiation to cause bond vibrations, used primarily to determine the presence of functional groups.

UV Spectroscopy

Determines the presence or absence of conjugated pi-bonds; conjugated dienes usually have absorption maxima longer than 200\text{\textunits{nm}}.

Nuclear Magnetic Resonance (NMR)

A technique that observes the carbon framework and structure of a compound by measuring the absorption of energy by nuclei in a strong magnetic field.

Mass Spectrometry (MS)

A method involving the bombardment of molecules with high-energy electrons to determine molecular weight and fragmentation patterns.

Base Peak

The tallest peak in a mass spectrum, representing the most abundant ion.