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Difference between revisions of "Template:Keywords: Charge"

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(Created page with "== Terms and symbols in the context of charge == === Charge of the proton ''versus'' charge per proton === :::: Proton charge is the elementary charge ''e'' [C·x<sup>-1</su...")
 
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== Terms and symbols in the context of charge ==
== 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> ===


=== 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>]


:::: IUPAC defines the charge number of an ion as: ''z''<sub>B</sub> = ''Q''<sub>B</sub>/''e''. 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.
''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 15:28, 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 = zBe. 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]
eQUH+ = QelH+·NH+-1 [C∙x-1]

Keywords

» charge QelX
» charge number zX
» electrochemical constant f
» elementary charge e
» Faraday constant F
» particle charge QUX


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SI-units.png

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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]