Terms starting with P
72 terms · page 2 of 3
Phenolphthalein
An acid–base indicator that is colourless in acid and pink in alkaline solution, changing between pH 8.3 and 10.0.
Biochemistry & Polymer ChemistryPhospholipid
A lipid in which one fatty acid of a triglyceride is replaced by a phosphate-containing group.
Chemical Kinetics & CatalysisPhotochemical Quantum Yield
The number of molecules reacting for each photon of light absorbed by the system.
Stoichiometry & Chemical ReactionsPhotochemical Reaction
A reaction initiated by the absorption of light, which promotes a molecule to an electronically excited state.
Biochemistry & Polymer ChemistryPhotosynthesis
The process by which plants use light energy to convert carbon dioxide and water into carbohydrate and oxygen.
Foundations of ChemistryPhysical Change
A change that alters the form or state of a substance while leaving its chemical composition intact.
Chemical EquilibriumPhysical Equilibrium
An equilibrium between two physical states or phases of the same substance.
Foundations of ChemistryPhysical Property
A characteristic of a substance that can be observed or measured without altering its chemical identity.
Chemical Kinetics & CatalysisPhysisorption
Weak adsorption in which molecules are held to a surface by van der Waals forces alone.
Chemical Bonding & Molecular StructurePi Bond
A covalent bond formed by the sideways overlap of parallel p orbitals, with electron density above and below the internuclear axis.
Acids, Bases & SaltspKa
The negative logarithm of the acid dissociation constant, giving a convenient scale of acid strength.
Acids, Bases & SaltspKb
The negative logarithm of the base dissociation constant.
States of Matter & Gas LawsPlasma
A state of matter consisting of a hot, electrically conducting mixture of ions and free electrons.
Atomic Structure & PeriodicityPlum Pudding Model
J. J. Thomson's 1904 model picturing the atom as a sphere of diffuse positive charge with electrons embedded within it.
Acids, Bases & SaltspOH
The negative logarithm of the hydroxide ion concentration.
Chemical Bonding & Molecular StructurePolar Covalent Bond
A covalent bond in which the shared electrons are unequally distributed because the bonded atoms differ in electronegativity.
Chemical Bonding & Molecular StructurePolarisability
The ease with which the electron cloud of an atom, ion or molecule can be distorted by an external electric field.
Chemical Bonding & Molecular StructurePolarising Power
The ability of a cation to distort the electron cloud of a neighbouring anion.
Foundations of ChemistryPolyatomic Ion
A covalently bonded group of atoms that carries an overall electrical charge and behaves as a single unit in reactions.
Inorganic & Coordination ChemistryPolydentate Ligand
A ligand that binds to a single metal centre through three or more donor atoms.
Biochemistry & Polymer ChemistryPolymer
A large molecule built from many repeating structural units joined by covalent bonds.
States of Matter & Gas LawsPolymorphism
The ability of a single substance to exist in more than one crystalline form.
Acids, Bases & SaltsPolyprotic Acid
An acid capable of donating more than one proton per molecule.
Biochemistry & Polymer ChemistryPolysaccharide
A carbohydrate polymer built from many monosaccharide units linked by glycosidic bonds.