Organic Chemistry Laboratory Techniques and Theory

Comprehensive vocabulary flashcards covering common organic chemistry laboratory techniques, apparatus, chromatography behavior, and spectroscopy interpretation based on lecture notes.

Stationary Phase (TLC)

The phase in Thin Layer Chromatography, typically consisting of polar silica gel.

Mobile Phase (TLC)

The solvent or eluent used to move compounds across the TLC plate.

Low Rf Value

Indicates a more polar compound that interacts more strongly with the polar silica gel.

High Rf Value

Indicates a less polar compound that has less interaction with the stationary phase.

Rf Equation

$$Rf = \frac{\text{distance traveled by compound}}{\text{distance traveled by solvent front}}$$

Effect of Hexane on Rf

Causes Rf values to decrease because the solvent becomes less polar.

Polarity Order of Analgesics

Ibuprofen < aspirin < acetaminophen < caffeine (from least to most polar).

Liquid-Liquid Extraction

A technique used to separate compounds based on their relative solubility in immiscible solvents.

Separatory Funnel Venting

The process of releasing pressure buildup during a liquid-liquid extraction.

Dichloromethane Layer

Determines the bottom layer in an extraction due to its density.

Drying Agents

Substances like anhydrous sodium sulfate or magnesium sulfate used to remove residual water from organic solutions.

Brine

A saturated salt solution used during extraction to help remove water.

Simple Distillation

Used to separate liquids with significantly different boiling points.

Fractional Distillation

Used to separate liquids with boiling points that are close together by using a fractionating column.

Fractionating Column

An apparatus that allows for repeated vaporization-condensation cycles to improve the separation of liquids.

Boiling Chips

Granules added before heating to prevent superheating and bumping of the liquid.

Condenser

Apparatus used to cool vapor back into a liquid; water must enter from the bottom to keep the jacket completely full.

Recrystallization Solvent

A solvent where the solid is soluble when hot and insoluble when cold.

Slow Cooling in Recrystallization

A cooling process that allows for the formation of larger, purer crystals.

Rapid Cooling in Recrystallization

A process that results in the formation of small, impure crystals.

Hot Gravity Filtration

A method to remove insoluble impurities from a hot solution using a short-stem funnel.

Vacuum Filtration

A fast method to collect crystals using a Büchner funnel and a vacuum flask.

Pure Compound Melting Point

Melts over a sharp, narrow temperature range.

Impure Compound Melting Point

Melts at a temperature that is lower and has a broader range than the pure substance.

Mixed Melting Point

A technique where a depressed and broad melting range indicates that two combined compounds are different.

Carbonyl Peak (IR)

A typically strong peak located around $1700\,\text{cm}^{-1}$.

Alcohol O-H Peak (IR)

A broad peak found in the range of $3200\text{--}3600\,\text{cm}^{-1}$.

Nitrile Peak (IR)

Peak located around $2250\,\text{cm}^{-1}$.

Column Chromatography Stationary Phase

Consists of alumina or silica gel; more polar compounds elute more slowly through it.

Volumetric Flask

The most accurate glassware for measuring or preparing one exact volume.

Mel-Temp

A specific apparatus used to measure the melting point of a solid.

Erlenmeyer Flask

Glassware designed with a tapered neck best suited for swirling liquids.

Reflux

A technique using a round-bottom flask and condenser to heat a reaction continuously without losing solvent.

Acetic Acid in TLC

An additive in the solvent used to reduce streaking and tailing on the plate.