Temperature at which all substances have no thermal energy; 0Kevin or -273C.
Acid dissociation constant (Ka)
The equilibrium constant that measures the degree of dissociation for an acid under specific conditions.
For an acid HA,
Ka= [H+][A-] / HA
Activation energy (Ea)
Minimum amount of energy required for a reaction to occur.
An ionic species with a negative charge.
The electrode at which oxidation occurs.
The averaged mass of the atoms of an element, taking into account the relative abundance of the various isotopes in a naturally occuring substance.
(a.k.a atomic weight)
Atomic mass unit (amu)
A unit of mass defined as 1/12 the mass of a carbon-12 atom; approximately equal to the mass of one proton or one neutron
The number of protons in a given element (nuclear charge)
The square of the wavefunction of an electron It describes the region of space where there is a high probability of finding the electron
The principle that electrons fill energy levels in a given atom in order of increasing energy, completely filling one sublevel before beginning to fill the next
The number of atoms of molecules in one mole of a substance: 6.022 x 1023
The law stating that under the same conditions of temperature and pressure, equal volumes of different gases will have the same number of molecules
Azimuthal quantum number (l)
The second quantum number, denoting the sublevel or subshell in which an electron can be found. Reveals the shape of the orbital. This quantum number represents the orbital angular momentum of te motion of the electron about a point in space
An equation for a chemical reaction in which the number of atoms for each element in the reaction and the total charge are the same for the reactants and the products
A species that donates hydroxide ions or electrons or that accepts protons
Base dissociation constant (Kb)
The equilibrium constant that measures the degree of dissociation for a base under specific conditions
For a base BOH,
Kb= [B+][OH-] / [BOH]
An aqueous solution that contains more OH- ions than H+ ions. The pH of a basic solution is greater than 7
The model of the hydrogen atom postulating that atoms are composed of electrons that assume certain circular orbits about a positive nucleus