Stoichiometry & Chemical Reactions — 60 Terms Defined

Gay-Lussac's Law of Combining Volumes Stoichiometry & Chemical Reactions L The principle that gases react in volume ratios that are simple whole numbers, when measured at the same temperature and pressure. V_A : V_B = a : b

Half-Reaction Method Stoichiometry & Chemical Reactions Dimensionless A technique for balancing redox equations by splitting them into separate oxidation and reduction half-equations. balance atoms, then O with H₂O, H with H⁺, charge with e⁻

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

Hydrolysis Stoichiometry & Chemical Reactions Dimensionless A reaction in which a bond is cleaved by water, with the H and OH fragments adding to the two products. AB + H₂O → AOH + BH

Irreversible Reaction Stoichiometry & Chemical Reactions Dimensionless A reaction that proceeds essentially to completion, with negligible conversion back to reactants. A + B → C

Law of Reciprocal Proportions Stoichiometry & Chemical Reactions Dimensionless The principle that the mass ratios in which two elements combine with a third are related by a simple ratio to the ratio in which they combine with each other.

Limiting Reagent Stoichiometry & Chemical Reactions mol The reactant that is completely consumed first and therefore determines the maximum amount of product obtainable. smallest n / coefficient

Mole Ratio Stoichiometry & Chemical Reactions Dimensionless The proportion between the amounts of any two substances in a reaction, taken directly from the balanced equation's coefficients. n_A : n_B = a : b

Molecular Equation Stoichiometry & Chemical Reactions Dimensionless A chemical equation in which all reactants and products are written as complete, undissociated formulae. AgNO₃(aq) + NaCl(aq) → AgCl(s) + NaNO₃(aq)

Net Ionic Equation Stoichiometry & Chemical Reactions Dimensionless An equation showing only the species that actually change during a reaction, with all spectator ions removed. Ag⁺(aq) + Cl⁻(aq) → AgCl(s)

Neutralisation Reaction Stoichiometry & Chemical Reactions kJ/mol The reaction between an acid and a base to produce a salt and water. HA + BOH → BA + H₂O

Oxidation Number Method Stoichiometry & Chemical Reactions Dimensionless A technique for balancing redox equations by equating the total increase and decrease in oxidation numbers. Σ increase = Σ decrease

Percentage Purity Stoichiometry & Chemical Reactions Dimensionless The proportion of a sample that consists of the desired compound, expressed as a percentage of the total mass. % purity = (mass pure / mass sample) × 100

Percentage Yield Stoichiometry & Chemical Reactions Dimensionless The actual yield expressed as a percentage of the theoretical yield. % yield = (actual / theoretical) × 100

Photochemical Reaction Stoichiometry & Chemical Reactions nm A reaction initiated by the absorption of light, which promotes a molecule to an electronically excited state. A + hν → A*

Precipitate Stoichiometry & Chemical Reactions g An insoluble solid that separates from a solution as the result of a chemical reaction.

Precipitation Reaction Stoichiometry & Chemical Reactions Dimensionless A reaction in which two solutions combine to form an insoluble solid that separates from the mixture. A⁺(aq) + B⁻(aq) → AB(s)

Product Stoichiometry & Chemical Reactions mol A substance formed as a result of a chemical reaction.

Pyrolysis Stoichiometry & Chemical Reactions °C The thermal decomposition of a substance at high temperature in the absence of oxygen. complex → simpler fragments (Δ, no O₂)

Reactant Stoichiometry & Chemical Reactions mol A starting substance that is consumed during a chemical reaction.

Rearrangement Reaction Stoichiometry & Chemical Reactions Dimensionless A reaction in which the atoms of a molecule are reorganised to give a structural isomer. A → A′ (isomer)

Redox Reaction Stoichiometry & Chemical Reactions V A reaction in which electrons are transferred, so that one species is oxidised while another is reduced. Ox₁ + Red₂ → Red₁ + Ox₂

Reversible Reaction Stoichiometry & Chemical Reactions Dimensionless A reaction that can proceed in both the forward and reverse directions under the same conditions. A + B ⇌ C + D

Roasting Stoichiometry & Chemical Reactions °C The heating of a sulfide ore strongly in a plentiful supply of air to convert it into the oxide. 2MS + 3O₂ → 2MO + 2SO₂