Definitions - Organic Chemistry II - AQA Chemistry A-level

Chiral Carbon

An asymmetric carbon atom bound to 4 different groups.

Displayed Formula

Shows all bonds between every atom in a compound.

Enantiomers

Non-superimposable mirror image molecules.

Optical Isomerism

Stereoisomerism due to a chiral centre.

Racemic Mixture

Equal mix of enantiomers in a mixture.

Stereoisomers

Compounds differing in spatial atom arrangement.

Structural Formula

Shows atom arrangement without bond details.

Aldehyde

Molecule with C=O group at the end.

Carbonyl Group

Functional group with C=O double bond.

Curly Arrow

Indicates electron pair movement in mechanisms.

Hydroxynitrile

Molecule with OH and C≡N on the same carbon.

Ketone

Molecule with C=O group in the middle.

Nucleophile

Electron pair donor in reactions.

Nucleophilic addition-elimination

Process of adding a nucleophile, breaking a π bond, and removing a leaving group

Primary Amide

Molecule with a specific functional group

Recrystallisation

Technique for purifying compounds through solvent dissolution and filtration

Acyl Group

Group with a specific structure, where R is an alkyl group

Addition Reaction

Chemical reaction forming a single product from combining molecules

Aromatic Compound

Compound containing at least one benzene ring

Benzene

6-membered carbon ring with a delocalised π system

Delocalisation of p electrons

Overlap of empty p orbitals in benzene forming a stable π system

Electrophile

Chemical species accepting an electron pair

Electrophilic Substitution

Reaction where an electrophile replaces atoms in a compound

Enthalpy of Hydrogenation

Enthalpy change when unsaturated compound reacts with hydrogen

Friedel-Crafts Acylation

Synthetic reaction forming monoacylated benzene rings using AlCl3

Monosubstituted benzene ring

Benzene ring with one hydrogen replaced by another group

Nitration

Synthesis reaction using nitric acid to substitute atoms in benzene

Substitution Reaction

Reaction where atoms/groups are replaced by others in a compound

Aliphatic

Organic compounds with carbon atoms in chains

Alkyl group

Group derived from an alkane by removing a hydrogen atom

Amines

Compounds derived from ammonia by replacing hydrogen with alkyl/aryl groups

Aromatic Amines

Organic compounds with R-NH2 structure, important in dye manufacturing

Aryl group

Group derived from a benzene ring by removing a hydrogen atom

Lone Pair

Pair of valence electrons not involved in bonding

Nucleophilic substitution

Reaction where nucleophile replaces atoms in a compound

Primary aliphatic amines

Organic compound with R-NH2 structure, prepared from ammonia and halogenoalkanes

Primary ammonium salt

Organic compound formed from halogenoalkane and ammonia reaction

Quaternary ammonium salts

Organic compounds formed from halogenoalkane and tertiary amine reaction

Secondary ammonium salt

Formed from a halogenoalkane and a primary amine

Tertiary ammonium salt

Result of a halogenoalkane reacting with a secondary amine

Addition Polymer

Long chain molecule where many monomers join

Biodegradable

Substance decomposable by bacteria or living organisms

Condensation Polymer

Long chain molecule formed with monomers releasing small molecules

Hydrolysis

Reaction using water to break down a compound

Intermolecular Forces

Forces acting between molecules like dipole-dipole and hydrogen bonding

Monomer

Small molecule used to form polymers

Polyalkene

Addition polymer from joining alkene monomers

Polyamide

Condensation polymer from amino and carboxylic acid groups

Polyester

Condensation polymer from alcohol and carboxylic acid groups

Polymer

Large molecule from bonded small units

Repeating Unit

Structure appearing repeatedly in a polymer

Active Site

Region in an enzyme where substrate binds

Amino Acid

Organic compound with carboxyl and amino groups

Catalyst

Substance speeding up reaction rate without being consumed

Cisplatin

Pt(II) complex used as an anticancer drug

Developing Agents

Substances locating amino acids on a chromatogram

DNA (deoxyribonucleic acid)

Polymer of nucleotides with a double helix structure

Enzyme

Biological catalyst made of proteins

Enzyme Inhibitor

Substance reducing enzyme activity

Hydrogen Bonding

Intermolecular bond between hydrogen and electronegative atom

Ligand

Ion or molecule binding to a metal atom

Nucleotide

Molecule with phosphate, deoxyribose, and DNA bases

Pentose Sugar

Sugar molecule with 5 carbon atoms

Peptide Link

Bond between carboxyl and amino groups in proteins

Primary Protein Structure

Amino acid chain sequence in a protein

Protein

Molecule of amino acids joined by peptide bonds

Secondary Protein Structure

Structure with hydrogen bonds between amino acid chains, e.g., α-helix and β-pleated sheet

Substrate

Molecule binding to enzyme's active site during a reaction

Tertiary Protein Structure

Three-dimensional protein structure with ionic bonds, disulfide bridges, and more

Thin Layer Chromatography

Technique using solvent and silica-coated sheet to separate compounds like amino acids

Zwitterion

Molecule with separate positive and negative charged groups

Atom Economy

Measure of useful products from starting materials in organic synthesis

Organic Compound

Carbon-containing compound

Solvent

Liquid dissolving other substances

Synthesis

Combining elements to form new molecules

Aliphatic Compound

Organic compound with straight or branched chains

CCl4

Solvent commonly used in 1H NMR spectroscopy

Chemical Shift

Shift of carbon or proton environment relative to TMS standard

Coupling

Interaction between adjacent non-equivalent protons in NMR spectroscopy

Deuterated Solvent

Solvent with deuterium replacing hydrogen atoms