Chemistry terms starting with B

Body-Centred Cubic States of Matter & Gas Laws Dimensionless A cubic arrangement with particles at the eight corners plus one at the centre of the cell. 2 atoms per cell, 68% packing

Bohr Model Atomic Structure & Periodicity Dimensionless The 1913 model in which electrons orbit the nucleus in fixed circular paths of quantised energy and angular momentum. mvr = nh / 2π

Boiling Point States of Matter & Gas Laws °C The temperature at which the vapour pressure of a liquid equals the external pressure acting on it. p_vap = p_external

Boiling Point Elevation Solutions & Colligative Properties °C The rise in a solvent's boiling point caused by the presence of a non-volatile solute. ΔT_b = i K_b m

Bomb Calorimeter Thermochemistry & Thermodynamics J A rigid sealed vessel used to measure the heat released by combustion at constant volume. q_V = ΔU

Bond Angle Chemical Bonding & Molecular Structure degrees The angle between two bonds that share a common atom.

Bond Dissociation Enthalpy Thermochemistry & Thermodynamics kJ/mol The enthalpy change when one mole of a specific bond is broken homolytically in the gas phase. A–B(g) → A·(g) + B·(g)

Bond Energy Chemical Bonding & Molecular Structure kJ/mol The energy required to break one mole of a given bond homolytically in the gaseous state. A–B(g) → A(g) + B(g)

Bond Length Chemical Bonding & Molecular Structure pm The equilibrium distance between the nuclei of two bonded atoms. d ≈ r₁ + r₂

Bond Order Chemical Bonding & Molecular Structure Dimensionless The number of chemical bonds between a pair of atoms, or in molecular orbital terms half the difference between bonding and antibonding electrons. BO = (N_b − N_a) / 2

Bond Polarity Chemical Bonding & Molecular Structure Dimensionless The degree of unequal electron sharing in a covalent bond, arising from an electronegativity difference between the bonded atoms. Δχ = |χ_A − χ_B|

Bonding Molecular Orbital Chemical Bonding & Molecular Structure Dimensionless A molecular orbital lower in energy than the atomic orbitals from which it forms, whose occupation stabilises the molecule. ψ = ψ_A + ψ_B

Bonding Pair Chemical Bonding & Molecular Structure Dimensionless A pair of electrons shared between two atoms and responsible for holding them together.

Born–Haber Cycle Chemical Bonding & Molecular Structure kJ/mol A thermochemical cycle applying Hess's law to determine the lattice energy of an ionic compound indirectly. ΔH_f = ΔH_sub + IE + ½D + EA + U

Boyle's Law States of Matter & Gas Laws Pa·m³ At constant temperature, the volume of a fixed mass of gas is inversely proportional to its pressure. p₁V₁ = p₂V₂

Breeder Reactor Nuclear & Radiochemistry Dimensionless A reactor that produces more fissile material than it consumes by converting fertile nuclides. ²³⁸U + n → ²³⁹Pu

Brownian Motion Solutions & Colligative Properties m²/s The continuous random zigzag movement of colloidal particles caused by uneven bombardment from surrounding molecules. ⟨x²⟩ = 2Dt

Brønsted–Lowry Theory Acids, Bases & Salts Dimensionless The theory defining an acid as a proton donor and a base as a proton acceptor. HA + B ⇌ A⁻ + BH⁺

Buffer Capacity Acids, Bases & Salts mol/L The amount of strong acid or base a buffer can absorb before its pH changes appreciably. β = dn / d(pH)

Buffer Range Acids, Bases & Salts Dimensionless The span of pH values over which a buffer works effectively, conventionally one unit either side of its pKa. pH = pKa ± 1

Buffer Solution Acids, Bases & Salts Dimensionless A solution that resists changes in pH when small amounts of acid or base are added.

Terms starting with B