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 Abbreviated list of quantities, units and symbols in physical chemistry


Several physical quantites have more than one entry in the symbol column for different reasons:

  1. Both symbols are in use (e.g. p, P for pressure and q, Q for heat);
  2. Different symbols are used for the same physical quantity in different physical systems (for example, electron spin quantum number s for a single electron and S for the sum over several electrons);
  3. Alternative symbols are recommended to avoid conflict in the notation for quantities which otherwise would have the same symbols (e.g. Ea, to distinguish the energy of activation from another energy E in the same context. The unit 1 in the SI unit symbol column signifies a dimensionless quantity.

An extensive physical quantity, that is a quantity proportional to the mass of amount of substance of a system, is often symbolized by a capital letter. The corresponding specific quantity (quantity divided by mass) may be represented by the corresponding lowercase letter (example: volume V, specific volume v=V/m). A subscript m to the symbol of an extensive quantityt denotes a molar quantity (quantity divided by amount of substance), example: molar volume Vm=V/n. It is permissible to omit the subscript m for molar when the text makes it obvious that a molar quantity is intended.

Vectors are printed in bold-faced italic type. They can alternatively be indicated by an arrow above the symbol.


Page last modified 29 May 2000.
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