Search results for “pH”

Stationary Phase Analytical Chemistry & Spectroscopy Dimensionless The fixed material in a chromatographic system with which the sample components interact as they pass.

SN1 Reaction Organic Chemistry s⁻¹ A two-step nucleophilic substitution proceeding through a carbocation intermediate. rate = k[substrate]

SN2 Reaction Organic Chemistry L/(mol·s) A single-step nucleophilic substitution in which bond formation and bond breaking occur simultaneously. rate = k[substrate][nucleophile]

Solvent Extraction Equilibrium Chemical Equilibrium Dimensionless The equilibrium established when a solute is transferred between two immiscible liquid phases in a separating funnel. efficiency = P V₁ / (P V₁ + V₂)

Supercritical Fluid States of Matter & Gas Laws K, Pa A substance held above both its critical temperature and critical pressure, where liquid and gas phases are indistinguishable. T > T_c and p > p_c

Salt Acids, Bases & Salts Dimensionless An ionic compound formed when the hydrogen of an acid is replaced by a metal or other cation. acid + base → salt + water

Salt Hydrolysis Acids, Bases & Salts mol/L The reaction of a salt's ions with water to produce an acidic or alkaline solution. A⁻ + H₂O ⇌ HA + OH⁻

Scintillation Counter Nuclear & Radiochemistry counts/s A detector in which radiation causes a material to emit flashes of light that are counted and measured.

Second Law of Thermodynamics Thermochemistry & Thermodynamics J/K The total entropy of the universe increases in every spontaneous process. ΔS_universe > 0

Secondary Cell Electrochemistry & Redox V A cell whose reaction can be reversed by an applied current, allowing it to be recharged and reused.

Secondary Structure Biochemistry & Polymer Chemistry Dimensionless Local regular folding patterns of a polypeptide backbone stabilised by hydrogen bonds.

Secondary Valence Inorganic & Coordination Chemistry Dimensionless In Werner's theory, the non-ionisable valence corresponding to the coordination number, satisfied by ligands in fixed spatial positions.

Selective Precipitation Chemical Equilibrium mol/L The separation of ions from a mixture by adding a reagent that precipitates them one at a time.

Self-Ionisation of Water Acids, Bases & Salts mol/L The reaction in which two water molecules transfer a proton to give a hydronium and a hydroxide ion. 2H₂O ⇌ H₃O⁺ + OH⁻

SI Base Units Foundations of Chemistry Various The seven defined units of the International System from which every other measurement unit is derived.

Sievert Nuclear & Radiochemistry Sv The SI unit of equivalent dose, weighting absorbed dose by the biological damage the radiation type causes. H = D × w_R

Slag Inorganic & Coordination Chemistry Dimensionless The molten by-product formed when a flux combines with the gangue during smelting.

Solid State States of Matter & Gas Laws Dimensionless The state of matter in which particles are held in fixed positions, giving a definite shape and volume.

Solubility Rules Stoichiometry & Chemical Reactions Dimensionless A set of empirical guidelines predicting whether an ionic compound will dissolve appreciably in water.

Solution Solutions & Colligative Properties Dimensionless A homogeneous mixture in which one or more substances are dispersed uniformly at the molecular or ionic level in another.

Solvent Solutions & Colligative Properties L The component of a solution present in the greater amount, which dissolves and disperses the solute.

Standard Molar Entropy Thermochemistry & Thermodynamics J/(mol·K) The absolute entropy of one mole of a substance in its standard state at 298 K. ΔS° = ΣS°(products) − ΣS°(reactants)

Starch Biochemistry & Polymer Chemistry Dimensionless The storage polysaccharide of plants, consisting of amylose and amylopectin. (C₆H₁₀O₅)ₙ

Stepwise Ionisation Acids, Bases & Salts mol/L The successive loss of protons from a polyprotic acid, each governed by its own equilibrium constant. Ka₁ ≫ Ka₂ ≫ Ka₃

Results for “pH”