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Showing 61–90 of 1709 reference entries

Physics · MeasurementElectric current

Current measures charge crossing a chosen surface per unit time.

DefinitionPhysicsElectric field and force

An electric field assigns force per unit test charge.

DefinitionPhysicsMagnetic force on a moving charge

Magnetic force depends on charge motion relative to the field.

ModelPhysicsOhm's law and its domain

A linear current-voltage relation requires suitable conditions.

Empirical findingPhysicsFirst law of thermodynamics

Keep the heat and work sign convention explicit in an energy balance.

ModelPhysicsSecond law: isolated-system entropy

Apply entropy increase to the whole isolated system.

ModelPhysics · ChemistryIdeal-gas equation of state

A simple gas model relates pressure, amount, volume and temperature.

ModelPhysicsPhoton energy and frequency

One photon's energy is proportional to its frequency.

ModelPhysics · Mathematics & logicInvariant spacetime interval

Lorentz transformations preserve a combined space-time separation.

ModelPhysicsNewton's third law

Interaction forces act on different bodies in equal and opposite pairs.

ModelPhysicsAngular momentum and torque

Torque changes angular momentum about a specified origin.

ModelPhysicsHydrostatic pressure

Static fluid pressure rises with depth under gravity.

ModelPhysicsArchimedes' buoyancy principle

The hydrostatic upward force equals displaced-fluid weight.

ModelPhysicsMaxwell equations in free space

Four field equations connect electric and magnetic fields with charge and current.

ModelPhysicsSchrödinger time evolution

A quantum wavefunction evolves according to its Hamiltonian.

ModelPhysicsBorn position probability

A normalized wavefunction assigns probabilities to position intervals.

ModelPhysics · MeasurementElementary charge

The elementary charge has an exact SI numerical value.

DefinitionPhysics · MeasurementBoltzmann constant

The Boltzmann constant has an exact SI numerical value.

DefinitionMeasurement · Chemistry · PhysicsAvogadro constant

The mole is linked to a specified number of entities.

DefinitionMeasurement · PhysicsSI defining luminous efficacy

A specified frequency fixes the photometric SI reference.

DefinitionChemistryAtoms and elemental identity

The proton count of an atomic nucleus identifies its chemical element.

DefinitionChemistryIsotopes and mass number

Isotopes share a proton count but have different neutron counts.

DefinitionChemistryPeriodic organization of the elements

Atomic-number order reveals recurring patterns in electron structure and chemical properties.

ModelChemistryChemical bonds

Bonding describes interactions that bind atoms into molecules or extended structures.

DefinitionChemistry · MeasurementMole and amount of substance

The mole counts specified entities using the exact Avogadro constant.

DefinitionChemistryReaction stoichiometry

Balanced coefficients relate the amounts consumed and produced by a reaction.

MethodChemistryBalancing atoms and electric charge

A chemical equation must preserve each element's atom count and the total charge.

MethodChemistryDynamic chemical equilibrium

At equilibrium, opposing reactions continue without net composition change.

ModelChemistryBrønsted acids and bases

In the Brønsted description, an acid donates a proton and a base accepts it.

DefinitionChemistryGibbs energy and thermodynamic direction

Gibbs-energy change distinguishes thermodynamic favourability from reaction speed.

Model
DefinitionSource checked

Brønsted acids and bases

Chemistry

In the Brønsted description, an acid donates a proton and a base accepts it.

Key knowledge

A Brønsted acid is a proton donor and a Brønsted base is a proton acceptor. After donating a proton, an acid becomes its conjugate base; after accepting one, a base becomes its conjugate acid.

Conditions and scope

  • This is the Brønsted proton-transfer description, not the broader Lewis acid/base description.
  • Acid or base behaviour depends on the reaction partner and medium; water can take either role.
Sources · 2

References

Sources retain their recorded scope. A source link alone does not establish verification of every statement.

  1. Chemistry 2e, 14.1: Brønsted-Lowry Acids and BasesPaul Flowers, Klaus Theopold, Richard Langley and William R. Robinson — OpenStax, Rice UniversityTextbook chapteropenstax.orgRead source
  2. Physical Sciences 12: Acids and basesSiyavulaTextbook chaptersiyavula.comRead source

Evidence and review

Published proton-transfer and conjugate-pair definitions, including water/ammonia examples.

2026-10-10 · English donor/acceptor roles and conjugate pairing checked against section 14.1; no pH or strength value is claimed.

Foundational review

2026-10-10 · Fresh primary-source inspection of the complete compact record, including every statement, equation, quantity and material condition, followed by independent AI editorial review. This check does not certify all linked lessons or every passage of every cited publication.

Sources from other places

Agreement within this scope

Proton donation/acceptance and conjugate pairs.

Acid and base roles depend on the reaction partner.

Related reference entries

Explore relationships within this area of study and its connections to other areas.

Showing 1–3 of 3 relationships

Scientific relationships · 3 / 3

The relationship type describes the connection. Its linked statements, sources and conditions define the scope.

  1. Related to
    Relationship sources · 1

    Linked statements

    • A solution containing suitable amounts of a weak acid and its conjugate base, or the corresponding weak-base pair, can resist pH changes from added acid or base. This response follows coupled acid–base equilibria and has finite capacity.

    Buffer behaviour involves a weak acid/conjugate-base or corresponding base pair.

  2. Uses definition
    Relationship sources · 1

    Linked statements

    • For HA ⇌ H⁺ + A⁻ in a stated solvent convention, Ka relates the equilibrium activities. For a conjugate acid–base pair in water, KaKb=Kw under consistent definitions. Acid strength describes the equilibrium tendency to transfer a proton, while the fraction ionized also depends on composition.

    Ka quantifies a specified Brønsted proton-transfer equilibrium.

  3. Related to
    Relationship sources · 1

    Linked statements

    • Hydrogen in an ionic hydride is formally H− and can act as a strong base or reducing species; proton transfer with water produces hydrogen gas and hydroxide. Molecular hydrogen compounds instead have bonding and acid/base properties set by their partner elements and structure. A formula containing hydrogen does not imply hydride-like reactivity.

    Proton transfer explains the base reaction.

Entry detailsPermanent link to this entry ↗
Record identity
chem-acids-bases
Revision
core.1
Structured reference record
Essential core · first collection