USC Organic Chemistry Review for Chemical Technician Licensure Exam

Organic Chemistry Review

Structure of Urea

• The carbon atom in urea is sp3 hybridized.

Functional Groups

• Camphor is a terpene with a carbonyl functional group.
• Coniine is an alkaloid with an amine functional group.

Solubility

• Ethyl alcohol is more soluble in water than dichloromethane, cyclohexane, and chloroform.
• The order of increasing volatility is: CH4, CH2Cl2, CH3Cl, CHBr3.

IUPAC Nomenclature

• The correct IUPAC name for a given compound is determined by the structure of the compound.
• Examples: 1-chloro-2-methylpropane, 2-chloro-2-methylbutane, 4,5-dimethyl-1-hexene.

Constitutional Isomers

• Constitutional isomers are molecules with the same molecular formula but different structures.
• Examples: CH3CH2OCH3 and CH3CH2CHO, CH3CH2CH2CHO and CH3COCH2CH3.

Physical Properties

• The boiling point of a compound is related to the strength of intermolecular forces.
• The order of increasing boiling points is: butane, butanone, 1-butanol, butanoic acid.

Spectroscopy

• Infrared (IR) spectroscopy is used to determine the structure of organic molecules.
• Different functional groups absorb at specific wavenumbers in the IR spectrum.
• Examples: N-H, C-H, and O-H stretching and bending motions absorb at 4000-2500 cm-1.

Filtration Techniques

• Vacuum filtration is used to collect filtrate.
• Gravity filtration is used to collect crystals.
• Hot gravity filtration is used to filter hot solutions.

Recrystallization

• Recrystallization is a purification technique used to separate a solid from a solution.
• A good recrystallization solvent should have a high solubility for the solid at high temperatures and a low solubility at low temperatures.

Melting Point

• The melting point of a pure substance is the temperature at which the solid begins to melt.
• The melting point of a mixture is lower than that of a pure substance.

Distillation

• Distillation is a purification technique used to separate a mixture based on boiling points.
• A fractionating column is used to separate a mixture of compounds with similar boiling points.

Laboratory Techniques

• Ground glass joints are used to connect glassware.
• Grease is used to lubricate ground glass joints.
• A drying tube is used to dry a reaction mixture.
• A reflux condenser is used to convert vapors into a liquid during distillation.### Laboratory Techniques and Safety

Measurement and Heating Techniques

• A glass pipette is accurate for measuring 50 μL solutions.
• Analytical balances can measure solid samples up to 0.0001 g.
• A heat gun should not be used for microscale reactions.
• Steam baths are suitable for heating flammable solvents.
• Water baths can heat solvents below 90°C.

Chromatography

• Thin-Layer Chromatography (TLC) can determine sample purity and identity.
• TLC plates must not be heated before use.
• Concentrated samples should not be spotted repeatedly on TLC plates.
• The Rf value depends on the polarity of the substance and the stationary phase.

Column Chromatography

• Reverse-phase chromatography has a non-polar stationary phase and a polar mobile phase.
• In Reverse-Phase Chromatography, the longer the retention time, the stronger the affinity to the stationary phase.
• The area under the elution band indicates the quantity of the solute.

Gas Chromatography

• Helium, nitrogen, and argon are common carrier gases for GC.
• Open tubular or capillary columns are preferred over packed tubular columns for better resolution.

Headspace Analysis

• Headspace analysis is used to analyze volatile compounds from solid or liquid samples.

Laboratory Safety

• Gloves: Nitrile gloves are suitable for handling concentrated hydrochloric acid, while butyl gloves are not.
• In case of an earthquake, duck, cover, and hold first.
• Ethanol vapour can catch fire at temperatures above 13°C.
• Waste liquids with pH ≤ 2 or ≥ 12.5 are corrosive.
• The GHS pictogram indicates the type of hazard.

Safety Data Sheets (SDS)

• The SDS provides information on handling and storage, exposure control, and emergency procedures.
• Two signal words (Danger and Warning) indicate the relative level of severity of hazard.
• End-users should have access to the SDS.

Chemical Regulation and Inventory

• The Chemical Control Order (CCO) regulates mercury, cyanide, and polychlorinated biphenyls.
• Regular physical chemical inventory updates eliminate unneeded chemicals and ensure safe storage.

Emergency Preparedness and Response

• Emergency equipment should be easily accessible and regularly inspected.
• Mitigation phase efforts minimize the likelihood of incidents and limit their effects.

Green Chemistry

• Green Chemistry aims to reduce or eliminate the use and generation of hazardous substances.