Browse the dictionary
960 terms · page 3 of 40
Anodising
An electrolytic process that thickens the natural protective oxide layer on a metal, especially aluminium.
Organic ChemistryAnti-Markovnikov Addition
Addition in which the hydrogen attaches to the carbon bearing fewer hydrogens, reversing the normal regiochemistry.
Chemical Bonding & Molecular StructureAntibonding Molecular Orbital
A molecular orbital higher in energy than its parent atomic orbitals, whose occupation destabilises the molecule.
Chemical EquilibriumApproach to Equilibrium
The time-dependent process by which a reacting system moves towards its equilibrium composition.
Solutions & Colligative PropertiesAqueous Solution
A solution in which water is the solvent, denoted by the state symbol (aq).
Organic ChemistryArene
An aromatic hydrocarbon containing one or more benzene rings.
Organic ChemistryAromaticity
The special stability of planar cyclic molecules with a continuous, fully conjugated system of delocalised pi electrons.
Chemical Kinetics & CatalysisArrhenius Equation
The equation describing how a rate constant varies with temperature and activation energy.
Acids, Bases & SaltsArrhenius Theory
The theory defining an acid as a substance that produces H⁺ ions in water and a base as one that produces OH⁻ ions.
Nuclear & RadiochemistryArtificial Radioactivity
Radioactivity in nuclides created by bombarding stable nuclei with particles rather than found in nature.
Solutions & Colligative PropertiesAssociation
The joining of solute molecules in solution into larger aggregates, reducing the effective number of particles.
Chemical EquilibriumAssociation Constant
The equilibrium constant for the combination of two species into a single associated entity, the reciprocal of the dissociation constant.
Foundations of ChemistryAtom
The smallest particle of an element that retains the chemical identity of that element.
Analytical Chemistry & SpectroscopyAtomic Absorption Spectroscopy
A technique that measures the concentration of a metal from the light its free gaseous atoms absorb.
Analytical Chemistry & SpectroscopyAtomic Emission Spectroscopy
A technique that identifies and quantifies elements from the light their excited atoms emit.
Atomic Structure & PeriodicityAtomic Emission Spectrum
The pattern of discrete wavelengths emitted when excited atoms of an element return to lower energy states.
Foundations of ChemistryAtomic Mass Unit
A mass unit defined as exactly one twelfth the mass of a free, unbound carbon-12 atom in its ground state.
Atomic Structure & PeriodicityAtomic Number
The number of protons in the nucleus of an atom, which uniquely identifies the element.
Atomic Structure & PeriodicityAtomic Orbital
A mathematical function describing the region around a nucleus where an electron of given energy is most likely to be found.
Atomic Structure & PeriodicityAtomic Radius
A measure of the size of an atom, usually taken as half the distance between the nuclei of two bonded identical atoms.
Foundations of ChemistryAtomicity
The number of atoms present in one molecule of an element.
Atomic Structure & PeriodicityAufbau Principle
The rule that electrons occupy the lowest-energy orbital available before filling higher-energy ones.
Chemical Kinetics & CatalysisAutocatalysis
Catalysis of a reaction by one of its own products.
States of Matter & Gas LawsAverage Kinetic Energy
The mean translational kinetic energy of the particles in a sample, dependent only on absolute temperature.