Terms starting with H
41 terms · page 2 of 2
Homologous Series
A family of compounds sharing the same functional group and general formula, with successive members differing by CH₂.
Biochemistry & Polymer ChemistryHormone
A chemical messenger released by one tissue that regulates the activity of cells elsewhere in the body.
Atomic Structure & PeriodicityHund's Rule of Maximum Multiplicity
The rule that electrons occupy degenerate orbitals singly with parallel spins before any orbital is doubly occupied.
Chemical Bonding & Molecular StructureHybridisation
The mixing of atomic orbitals on the same atom to form an equal number of new, equivalent orbitals suited to bonding.
Foundations of ChemistryHydrate
A crystalline compound in which a definite number of water molecules is incorporated into the lattice.
Inorganic & Coordination ChemistryHydrate Isomerism
Isomerism arising from water molecules occupying either the coordination sphere or lattice positions outside it.
Solutions & Colligative PropertiesHydration Energy
The energy released when one mole of gaseous ions is surrounded by water molecules to form a dilute aqueous solution.
Stoichiometry & Chemical ReactionsHydration Reaction
The addition of water across a multiple bond or the incorporation of water into a crystal lattice.
Organic ChemistryHydrocarbon
A compound composed exclusively of carbon and hydrogen.
Chemical Bonding & Molecular StructureHydrogen Bond
A strong dipole interaction between a hydrogen atom bonded to N, O or F and a lone pair on another such atom.
Electrochemistry & RedoxHydrogen–Oxygen Fuel Cell
A fuel cell in which hydrogen is oxidised at the anode and oxygen reduced at the cathode, producing only water.
Stoichiometry & Chemical ReactionsHydrolysis
A reaction in which a bond is cleaved by water, with the H and OH fragments adding to the two products.
Acids, Bases & SaltsHydrolysis Constant
The equilibrium constant for the hydrolysis of a salt ion in water.
Organic ChemistryHyperconjugation
The stabilising delocalisation of electrons from a sigma C–H bond into an adjacent empty or partly filled p orbital.
Solutions & Colligative PropertiesHypertonic Solution
A solution with a higher osmotic pressure than the one it is compared with, drawing water out of the more dilute side.
Solutions & Colligative PropertiesHypotonic Solution
A solution with a lower osmotic pressure than the one it is compared with, so water flows into the more concentrated side.
Organic ChemistryHückel's Rule
The rule that a planar cyclic conjugated system is aromatic if it contains 4n + 2 pi electrons.