Search results for “pH”

High-Performance Liquid Chromatography Analytical Chemistry & Spectroscopy min A technique in which a liquid mobile phase is pumped at high pressure through a column of very fine stationary phase.

Henderson–Hasselbalch Equation Acids, Bases & Salts Dimensionless The equation giving the pH of a buffer from the pKa of its acid and the ratio of conjugate base to acid. pH = pKa + log([A⁻]/[HA])

Heterogeneous Catalysis Chemical Kinetics & Catalysis Dimensionless Catalysis in which the catalyst is in a different phase from the reactants, usually a solid with gaseous or liquid reagents.

Heterogeneous Equilibrium Chemical Equilibrium Dimensionless An equilibrium involving species present in more than one phase.

Heterogeneous Mixture Foundations of Chemistry Dimensionless A mixture in which the components remain physically distinct, so composition varies from one region of the sample to another.

Hexagonal Close Packing States of Matter & Gas Laws Dimensionless A close-packed arrangement in which layers of spheres repeat in an ABAB sequence. 6 atoms per cell, 74% packing

Homogeneous Catalysis Chemical Kinetics & Catalysis Dimensionless Catalysis in which the catalyst is in the same phase as the reactants.

Homogeneous Equilibrium Chemical Equilibrium Dimensionless An equilibrium in which all the reacting species are present in the same phase.

Hydrate Isomerism Inorganic & Coordination Chemistry Dimensionless Isomerism arising from water molecules occupying either the coordination sphere or lattice positions outside it.

Haloalkane Organic Chemistry Dimensionless An alkane in which one or more hydrogen atoms have been replaced by halogen atoms. R–X (X = F, Cl, Br, I)

Halogens Atomic Structure & Periodicity Dimensionless The group 17 elements — fluorine through astatine — which are one electron short of a full outer shell. ns² np⁵

HOMO and LUMO Chemical Bonding & Molecular Structure eV The highest occupied and lowest unoccupied molecular orbitals, which together govern a molecule's reactivity and spectroscopy. ΔE = E_LUMO − E_HOMO

Homogeneous Mixture Foundations of Chemistry Dimensionless A mixture whose composition and properties are uniform throughout, with no visible boundary between the components.

Homologous Series Organic Chemistry Dimensionless A family of compounds sharing the same functional group and general formula, with successive members differing by CH₂. differ by −CH₂−

Hydrocarbon Organic Chemistry Dimensionless A compound composed exclusively of carbon and hydrogen. CₓH_y

Hyperconjugation Organic Chemistry kJ/mol The stabilising delocalisation of electrons from a sigma C–H bond into an adjacent empty or partly filled p orbital.

Hydration Reaction Stoichiometry & Chemical Reactions Dimensionless The addition of water across a multiple bond or the incorporation of water into a crystal lattice. C=C + H₂O → C(OH)–CH

Results for “pH”