Template:Keywords: Charge
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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 [Cยทx-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" โ 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 ฯ [Cยทm-3]. Dividing ฯ by the count concentration of electrons [xยทm-3], we obtain the unit [Cยทx-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 = QBยทe-1
- Therefore, QB = zBโe. 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 QNX [Cโx-1]. To avoid too long and multiple subscript levels, QNX is used instead of QUX, and the โelโ is dropped from QelNX. The particle charge QNH+ of the proton is defined as elementary charge e. Therefore, the charge number of the proton is zH+ = QNH+/e = 1. In summary:
zB = QNBยทe-1
QNB = QelBยทNB-1 [Cโx-1]
e โ QNH+ = QelH+ยทNH+-1 [Cโx-1]
Keywords
- ยป charge QelX
- ยป charge number zX
- ยป electrochemical constant f
- ยป elementary charge e
- ยป Faraday constant F
- ยป iconic symbols
- ยป particle charge QNX
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- Normalization of charge and iconic symbols
- Iconic symbols show the quantity, the format of the normalization in the subscript (N, n, e), and the entity specified in the subscript (X). The normalized quantities are per X. In the quantities QelX, NX, nX, VX, mX, the subscript X without attachment to a format indicates the quantity of X.
Quantity Unit Normalized for quantity Unit Iconic symbol Unit Practical symbol Quantity charge QelX [C] / count NX [x] = QNX [Cยทx-1] particle charge (IUPAC: QB) charge QelX [C] / amount nX [mol] = QnX [Cยทmol-1] charge number times Faraday constant charge QelX [C] / volume VX [m3] = QVX [Cยทm-3] ฯel charge density charge QelX [C] / mass mX [kg] = QmX [Cยทkg-1] specific charge count NX [x] / charge QelX [C] = NeX [xยทC-1] amount nX [mol] / charge QelX [C] = neX [molยทC-1] volume VX [m3] / charge QelX [C] = VeX [m3ยทC-1] ฯel-1 mass mX [kg] / charge QelX [C] = meX [kgยทC-1]