Organic Chemistry I Definitions (AQA) - Vocabulary Flashcards

Vocabulary flashcards covering key concepts, terms, and definitions from the Organic Chemistry I notes.

Chain isomers

Isomers that occur due to branching in the carbon chain.

Displayed formula

A structural representation showing all bonds between every atom in a molecule.

Empirical formula

The smallest whole-number ratio of atoms of each element in a compound.

E-Z isomerism

A stereoisomerism due to restricted rotation around the C=C bond; E vs Z depend on the positions of highest priority groups.

Free-radical

An uncharged species with an unpaired electron.

Functional group

The atom group responsible for the characteristic reactions of a compound.

Functional group isomers

Isomers that contain different functional groups, belonging to different homologous series.

General formula

An empirical-like formula representing the composition of all members of a class, e.g., CnH2n+2 for alkanes.

Homologous series

A series of compounds with the same functional group and similar chemical properties.

Molecular formula

The total number of atoms of each element in a molecule.

Position isomer

Isomers with the same carbon backbone but different positions of a functional group.

Skeletal formula

A diagram where bonds are shown as lines and atoms are at line ends; hydrogens implied where not shown.

Stereoisomerism

Isomerism due to different spatial arrangements; includes E/Z isomerism from restricted rotation about C=C.

Structural formula

A formula showing the arrangement of atoms in a molecule without showing all bonds.

Structural isomerism

Isomers with the same molecular formula but different structural formulas.

Catalytic converter

Device in a car reducing emissions; uses platinum/rhodium catalysts on a ceramic honeycomb.

Catalytic cracking

Cracking at moderate pressure/temperature with a zeolite catalyst to produce fuels and aromatics.

Combustion of alkanes

Releases energy; complete combustion yields CO2 and H2O, incomplete yields CO and particulates.

Cracking

Breaking C–C bonds in alkanes to form shorter alkanes and alkenes.

Crude oil

Finite resource of hydrocarbons; remains of ancient biomass buried in rock.

Fractional distillation

Separation of mixtures by differing boiling points, used to divide crude oil into fractions.

Hydrocarbons

Compounds composed only of carbon and hydrogen.

Saturated

Compounds with only single C–C bonds; alkanes are saturated.

Thermal cracking

Cracking at high temperature and pressure producing more alkenes.

Chlorofluorocarbons (CFCs)

Carbon, chlorine and fluorine compounds that deplete the ozone and are banned in many applications.

Electrophile

Electron-pair acceptor attracted to electron-rich areas.

Elimination

Reaction where atoms or groups are removed to form a C=C bond.

Free radicals

Species with an unpaired electron; shown as a dot in mechanisms.

Free radical substitution

Photochemical reaction between halogens and alkanes forming halogenoalkanes via initiation, propagation, termination.

Nucleophile

Atom or molecule that donates an electron pair to form a covalent bond; attracted to electron-deficient areas.

Nucleophilic substitution

Reaction where a nucleophile replaces another group with the electrophile.

Ozone

O3 formed in the upper atmosphere; absorbs UV radiation, formed from O2 under UV light.

Ozone depletion

Chlorine atoms catalyse the breakdown of ozone, creating a hole in the ozone layer.

Polar bond

Covalent bond with unequal electron distribution, causing dipole; halogenoalkanes have polar bonds due to EN differences.

Addition polymer

Polymer formed by addition polymerisation from monomers with C=C bonds.

Addition polymerisation

Process by which many monomers (alkenes) add to form a long-chain polymer via opening their double bonds.

Alkenes

Hydrocarbons with a C=C double bond; unsaturated; general formula CnH2n.

Carbocation

Carbon atom bearing a positive charge.

Major/minor products

Major product forms from the most stable carbocation intermediate; minor from less stable ones.

Monomer

Small molecule that bonds with others to form a polymer.

Plasticiser

Additive that increases plasticity/flexibility of polymers, e.g., PVC.

Polymer

Large molecules made from many monomers bonded covalently.

Repeat unit

Part of a polymer that would be repeated to form the entire chain.

Unsaturated

Contains at least one C=C bond; alkenes are unsaturated.

Alcohols

Organic compounds containing the -OH functional group; first four members are methanol, ethanol, propanol, butanol.

Biofuel

Fuel derived from living matter, e.g., ethanol from glucose fermentation.

Carbon-neutral fuel

Fuel whose production and use result in no net increase in atmospheric CO2.

Classification of alcohols

Primary, secondary or tertiary depending on how many carbon groups bond to the carbon bearing the -OH.

Distillation

Process to separate liquids by their boiling points.

Fermentation of glucose

Industrial production of ethanol from glucose (from sugar cane) using yeast; anaerobic and warm.

Hydration of alkenes

Industrial process to make alcohols by reacting an alkene with steam in presence of an acid catalyst.

Oxidation of alcohols

Alcohols oxidized by acidified potassium dichromate; primary to aldehyde then to carboxylic acid; secondary to ketone; tertiary not easily oxidised.

Alcohol (Organic Analysis)

Alcohols contain -OH; identified by distillation with acidified potassium dichromate for primaries/secondaries.

Aldehyde

Contains C=O at the end of the molecule; reacts with Tollens’ reagent to give a silver mirror.

Alkene

Contains C=C; bromine water decolourises in the test for alkenes.

Carboxylic acid

Contains COOH; reacts with sodium carbonate to release CO2, turning limewater cloudy.

Fingerprint region

IR spectrum region below 1500 cm-1 that is unique to each molecule.

Infrared spectroscopy

Technique to identify bonds and functional groups; can also detect impurities.

Mass spectrometer

Instrument that gives accurate isotopic masses and relative abundances.

Mass Spectrometry

Technique to identify compounds and determine relative molecular mass.

Molecular Formula

Total number of atoms of each element in the compound.

Relative atomic mass

Average mass of an atom relative to 1/12 of carbon-12.

Relative molecular mass

Average mass of one molecule relative to 1/12 of carbon-12.

Wavenumber

Energy/frequency of infrared radiation absorbed by a bond; x-axis of IR spectra.