Search results for “pH”

Organic Chemistry Organic Chemistry Dimensionless The study of the structure, properties, composition and reactions of carbon-containing compounds.

Overpotential Electrochemistry & Redox V The extra voltage beyond the theoretical value that must be applied before an electrode reaction proceeds at a useful rate. η = E_applied − E_equilibrium

Polyatomic Ion Foundations of Chemistry C (charge) A covalently bonded group of atoms that carries an overall electrical charge and behaves as a single unit in reactions.

Polydentate Ligand Inorganic & Coordination Chemistry Dimensionless A ligand that binds to a single metal centre through three or more donor atoms.

Polyprotic Acid Acids, Bases & Salts mol/L An acid capable of donating more than one proton per molecule. H₂A ⇌ H⁺ + HA⁻ ⇌ 2H⁺ + A²⁻

Primary Standard Analytical Chemistry & Spectroscopy g/mol A highly pure, stable substance that can be weighed accurately and used directly to prepare a solution of known concentration.

Quantum Mechanical Model Atomic Structure & Periodicity Dimensionless The modern description of the atom in which electrons are represented by wavefunctions giving probability distributions rather than definite paths. Ĥψ = Eψ

Radioactive Tracer Nuclear & Radiochemistry Bq A radioisotope introduced into a system so that its pathway can be followed by detecting its radiation.

Radioactivity Nuclear & Radiochemistry Bq The spontaneous emission of particles or electromagnetic radiation from unstable atomic nuclei.

Rate-Determining Step Chemical Kinetics & Catalysis Dimensionless The slowest step in a reaction mechanism, which limits the overall rate.

Reaction Intermediate Chemical Kinetics & Catalysis mol/L A species produced in one step of a mechanism and consumed in a later one, so it does not appear in the overall equation.

Rydberg Formula Atomic Structure & Periodicity m⁻¹ The empirical equation predicting the wavelengths of the spectral lines emitted by a hydrogen-like atom. 1/λ = R_H(1/n₁² − 1/n₂²)

Second-Order Reaction Chemical Kinetics & Catalysis L/(mol·s) A reaction whose rate depends on the square of one concentration or on the product of two concentrations. 1/[A] = 1/[A]₀ + kt

Secondary Standard Analytical Chemistry & Spectroscopy mol/L A solution whose concentration has been established by titration against a primary standard.

Simultaneous Equilibria Chemical Equilibrium mol/L Several equilibria existing together in the same solution, all satisfied at once.

sp Hybridisation Chemical Bonding & Molecular Structure degrees The mixing of one s and one p orbital to give two linear hybrid orbitals at 180° to each other. 2 hybrids, 180°

Spontaneity Thermochemistry & Thermodynamics kJ/mol The tendency of a process to occur without any continuous external input of energy. ΔG < 0

Standard State Thermochemistry & Thermodynamics Dimensionless The reference condition of a pure substance at 1 bar pressure and a stated temperature, conventionally 298.15 K. denoted by °

Standardisation Analytical Chemistry & Spectroscopy mol/L The determination of the exact concentration of a solution by titrating it against a primary standard. M₁V₁ / n₁ = M₂V₂ / n₂

Surface Tension States of Matter & Gas Laws N/m The energy required to increase the surface area of a liquid by unit amount, arising from unbalanced intermolecular forces at the surface. γ = F / L

Surroundings Thermochemistry & Thermodynamics Dimensionless Everything outside the chosen system with which it can exchange energy or matter.

Thermodynamics Thermochemistry & Thermodynamics J The branch of science dealing with energy, its transformations, and the direction in which processes occur.

Titration Acids, Bases & Salts mol/L A quantitative technique in which a solution of known concentration is added to another until the reaction between them is exactly complete. n₁ / n₂ = a / b

Transition State Chemical Kinetics & Catalysis kJ/mol The highest-energy configuration along the reaction coordinate, at which bonds are partly broken and partly formed. denoted ‡

Results for “pH”