Template:Keywords: Charge: Difference between revisions
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== | == Canonical comments on IUPAC definitions in the context of charge == | ||
=== Charge of the proton ''versus'' charge per proton === | === Charge of the proton ''versus'' charge per proton === | ||
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:::: For comparison, the name "charge density of electrons" is used by IUPAC with symbol ''ρ'' [C·m<sup>-3</sup>]. Dividing ''ρ'' by the count concentration of electrons [x·m<sup>-3</sup>], we obtain the unit [C·x<sup>-1</sup>] for the electron charge. Therefore, electron charge (or proton charge) is clearly the charge '''''per''''' particle. | :::: For comparison, the name "charge density of electrons" is used by IUPAC with symbol ''ρ'' [C·m<sup>-3</sup>]. Dividing ''ρ'' by the count concentration of electrons [x·m<sup>-3</sup>], we obtain the unit [C·x<sup>-1</sup>] for the electron charge. Therefore, electron charge (or proton charge) is clearly the charge '''''per''''' particle. | ||
=== Ambiguity of ''Q''<sub>B</sub> === | |||
== | :::: IUPAC ([[Cohen 2008 IUPAC Green Book]]) defines the charge number as | ||
IUPAC: ''z''<sub>B</sub> = ''Q''<sub>B</sub>·''e''<sup>-1</sup> | |||
:::: Therefore, ''Q''<sub>B</sub> = ''z''<sub>B</sub>∙''e''. The subscript in ''Q''<sub>B</sub> indicates per elementary entity B. This is opposite to the subscript in ''V''<sub>B</sub> as the symbol for the volume of a substance of type B (e.g. ''V''<sub>O<sub>2</sub></sub> [L]). For consistency with this convention, the symbol ''Q''<sub>elB</sub> or ''Q''<sub>el''X''</sub> [C] is used for indicating charge of a substance of type B or ''X'', distinguished from particle charge as the quantity of charge per elementary entity ''X'' with symbol ''Q<sub><u>U</u>X</sub>'' [C∙x<sup>-1</sup>]. To avoid too long and multiple subscript levels, ''Q<sub><u>U</u>X</sub>'' is used instead of ''Q<sub>U<sub>X</sub></sub>'', and the ‘el’ is dropped from ''Q''<sub>el<u>''U''</u>''X''</sub>. The particle charge ''Q''<sub><u>''U''</u>H<sup>+</sup></sub> of the proton is defined as elementary charge ''e''. Therefore, the charge number of the proton is ''z''<sub>H<sup>+</sup></sub> = ''Q''<sub><u>''U''</u>H<sup>+</sup></sub>/''e'' = 1. In summary: | |||
''z''<sub>B</sub> = ''Q''<sub><u>''U''</u>B</sub>·''e''<sup>-1</sup> | |||
''Q''<sub><u>''U''</u>B</sub> = ''Q''<sub>elB</sub>·''N''<sub>B</sub><sup>-1</sup> [C∙x<sup>-1</sup>] | |||
''e'' ≝ ''Q''<sub><u>''U''</u>H<sup>+</sup></sub> = ''Q''<sub>elH<sup>+</sup></sub>·''N''<sub>H<sup>+</sup></sub><sup>-1</sup> [C∙x<sup>-1</sup>] | |||
=== Keywords === | === Keywords === |
Revision as of 16:28, 25 November 2020
Canonical comments on IUPAC definitions in the context of charge
Charge of the proton versus charge per proton
- Proton charge is the elementary charge e [C·x-1], which is charge QelH+ [C] of protons divided by the count NH+ [x] of protons. This distinction is not made sufficiently clear by IUPAC, when defining "-e is the charge of an electron" — it must be corrected to "-e is the charge per electron".
- For comparison, the name "charge density of electrons" is used by IUPAC with symbol ρ [C·m-3]. Dividing ρ by the count concentration of electrons [x·m-3], we obtain the unit [C·x-1] for the electron charge. Therefore, electron charge (or proton charge) is clearly the charge per particle.
Ambiguity of QB
- IUPAC (Cohen 2008 IUPAC Green Book) defines the charge number as
IUPAC: zB = QB·e-1
- Therefore, QB = zB∙e. The subscript in QB indicates per elementary entity B. This is opposite to the subscript in VB as the symbol for the volume of a substance of type B (e.g. VO2 [L]). For consistency with this convention, the symbol QelB or QelX [C] is used for indicating charge of a substance of type B or X, distinguished from particle charge as the quantity of charge per elementary entity X with symbol QUX [C∙x-1]. To avoid too long and multiple subscript levels, QUX is used instead of QUX, and the ‘el’ is dropped from QelUX. The particle charge QUH+ of the proton is defined as elementary charge e. Therefore, the charge number of the proton is zH+ = QUH+/e = 1. In summary:
zB = QUB·e-1
QUB = QelB·NB-1 [C∙x-1]
e ≝ QUH+ = QelH+·NH+-1 [C∙x-1]
Keywords
- » charge QelX
- » charge number zX
- » electrochemical constant f
- » elementary charge e
- » Faraday constant F
- » particle charge QUX
- Bioblast links: Charge - >>>>>>> - Click on [Expand] or [Collapse] - >>>>>>>
- Normalization of charge and canonical symbols
Quantity Unit Normalized for quantity Unit Canonical symbol Unit Practical symbol Quantity charge QelX [C] / count NX [x] = QUX [C·x-1] particle charge (IUPAC: QB) charge QelX [C] / amount nX [mol] = QnX [C·mol-1] charge number times Faraday constant charge QelX [C] / volume VX [m3] = QVX [C·m-3] ρel charge density charge QelX [C] / mass mX [kg] = QmX [C·kg-1] specific charge count NX [x] / charge QelX [C] = NeX [x·C-1] amount nX [mol] / charge QelX [C] = neX [mol·C-1] volume VX [m3] / charge QelX [C] = QVX [m3·C-1] ρel-1 mass mX [kg] / charge QelX [C] = MeX [kg·C-1]