Preferred Label : chemical flux;
Detailed label : chemical flux, φ;
IUPAC definition : A concept related to rate of appearance, particularly applicable to the progress in
one direction only of component reaction steps in a complex system or to the progress
in one direction of reactions in a system at dynamic equilibrium (in which there are
no observable concentration changes with time). Chemical flux is a derivative with
respect to time, and has the dimensions of amount of substance per unit volume transformed
per unit time. The sum of all the chemical fluxes leading to destruction of B is designated
the 'total chemical flux out of B' (symbol φ-B); the corresponding formation of B
by concurrent elementary reactions is the 'total chemical flux into B or A' (symbol
φB). For the mechanism: the total chemical flux into C is caused by the single reaction
(1): \[\sum Φ _{{C}} Φ _{1}\] whereas the chemical flux out of C is a sum over all
reactions that remove C: \[\sum Φ _{-{C}} Φ _{-1} Φ _{2}\] where φ-1 is the 'chemical
flux out of C into B (and/or A)' and φ 2 is the 'chemical flux out of C into E'. The
rate of appearance of C is then given by: \[\frac{{d}\left[{C}\right]}{{d}t} \sum
Φ _{{C}} - \sum Φ _{-{C}}\] In this system φ 1 (or φ-A) can be regarded as the hypothetical
rate of decrease in the concentration of A due to the single (unidirectional) reaction
(1) proceeding in the assumed absence of all other reactions. For a non-reversible
reaction: \[{A}\overset{1}{\rightarrow }{P}\] \[-\frac{{d}\left[{A}\right]}{{d}t}
Φ _{1}\] If two substances A and P are in chemical equilibrium: \[{A}\rightleftarrows
{P}\] then: \[\sum Φ _{{A}} \sum Φ _{-{A}} \sum Φ _{{P}} \sum Φ _{-{P}}\] and \[-\frac{{d}\left[{A}\right]}{{d}t}
\frac{{d}\left[{P}\right]}{{d}t} 0\];
Origin ID : C01024;
See also
A concept related to rate of appearance, particularly applicable to the progress in
one direction only of component reaction steps in a complex system or to the progress
in one direction of reactions in a system at dynamic equilibrium (in which there are
no observable concentration changes with time). Chemical flux is a derivative with
respect to time, and has the dimensions of amount of substance per unit volume transformed
per unit time. The sum of all the chemical fluxes leading to destruction of B is designated
the 'total chemical flux out of B' (symbol φ-B); the corresponding formation of B
by concurrent elementary reactions is the 'total chemical flux into B or A' (symbol
φB). For the mechanism: the total chemical flux into C is caused by the single reaction
(1): \[\sum Φ _{{C}} Φ _{1}\] whereas the chemical flux out of C is a sum over all
reactions that remove C: \[\sum Φ _{-{C}} Φ _{-1} Φ _{2}\] where φ-1 is the 'chemical
flux out of C into B (and/or A)' and φ 2 is the 'chemical flux out of C into E'. The
rate of appearance of C is then given by: \[\frac{{d}\left[{C}\right]}{{d}t} \sum
Φ _{{C}} - \sum Φ _{-{C}}\] In this system φ 1 (or φ-A) can be regarded as the hypothetical
rate of decrease in the concentration of A due to the single (unidirectional) reaction
(1) proceeding in the assumed absence of all other reactions. For a non-reversible
reaction: \[{A}\overset{1}{\rightarrow }{P}\] \[-\frac{{d}\left[{A}\right]}{{d}t}
Φ _{1}\] If two substances A and P are in chemical equilibrium: \[{A}\rightleftarrows
{P}\] then: \[\sum Φ _{{A}} \sum Φ _{-{A}} \sum Φ _{{P}} \sum Φ _{-{P}}\] and \[-\frac{{d}\left[{A}\right]}{{d}t}
\frac{{d}\left[{P}\right]}{{d}t} 0\]
