The characteristic wavelengths of electromagnetic radiation emitted or absorbed by an object,
atom, or molecule.
Spin quantum number (ms)
Spin quantum number (ms)
The fourth quantum number, indicating the orientation of the intrinsic angular momentum of
an electron in an atom. The spin quantum number can only assume values of or .
Spontaneous process
Spontaneous process
A process that will occur on its own without energy input from the surroundings.
Standard conditions
Standard conditions
Conditions defined as 25°C and 1 M concentration for each reactant in solution, and a partial
pressure of 1 atm for each gaseous reactant. Used for measuring the standard Gibbs free energy,
enthalpy, entropy, and cell EMF.
Standard free energy (G°)
Standard free energy (G°)
The Gibbs free energy for a reaction under standard conditions. See Gibbs free energy.
Standard hydrogen electrode (SHE)
Standard hydrogen electrode (SHE)
The electrode defined as having a potential of zero under standard conditions. All redox
potentials are measured relative to the standard hydrogen electrode. The potentials are measured
relative to the standard hydrogen electrode at 25°C and with 1.0 M of each ion in solution.