table of contents
CHEMEQ(1) | User Manuals | CHEMEQ(1) |
NAME¶
chemeq - Chemical Equation Parser and RendererSYNOPSIS¶
chemeq [-M] [-m] [-l] [-c]
[-w] [-C] [-e] [-s] [-n] [-W]
chemeq [-h] [-v]
DESCRIPTION¶
chemeq is a chemical equation analyzer. It is a fast lexical and syntaxic analyser which helps to find out chemical informations embedded in source chemical equations. Data can be output in various sophisticated formats, depending on options. 'chemeq' defaults to 'chemeq -mlcwCn'.OPTIONS¶
-MOutputs al list of space separated molecular
weights.
-m
Outputs a minimal output. It allows chemeq to be
idempotent, i.e. the command 'chemeq | chemeq' is equivalent to
'chemeq'.
-l
Outputs a LaTeX string representing the chemical
equation.
-c
Outputs a message giving informations about the
Conservation of elements and charges in the equation. 'OK' means that both
elements and electric charges are balanced.
-w
Outputs the LaTeX string representing the
Gulder-Waage equation related to the input chemical equation, or the
Nernst equation, if the input equation is a redox semi-equation.
-C
Outputs a detailed Count of the molecules and
atoms contained in each member of the chemical equation. For example for the
equation "H2_g + 1/2 O2_g --> H2O" it outputs: "H2_g|H:1*2,
1/2 O2_g|O:1/2*2; H2O|H:1*2 O:1*1"
-e
Outputs a detailed count of the Electrical
charges.
-s
Outputs a list of the chemical Species.
-n
Outputs a Normalized string accounting for the
input equation. Two chemical equations having the same normalized string are
chemically equivalent, even if the molecules are scrambled around and the
coefficient are not equal but proportionnal.
-W
Changes the behavior of the renderer for some versions of
Wims : works around a bug whith the macro \rightarrow.
-h
Displays Help.
-v
Displays the Version number
ENVIRONMENT¶
chemeq_input, w_chemeq_inputif set, this variables's value overrides the standard
input. If this variable is not set, the variable w_chemeq_input is taken in
account (useful for the WIMS server). See above (useful for the WIMS
server).
chemeq_option
if set, this variable's value overrides the options.If
this variable is not set, the variable w_chemeq_option is taken in account
(useful for the WIMS server).
w_chemeq_option
See above (useful for the WIMS server).
EXAMPLES¶
echo "1/2 Cu^2+ + OH- -> 1/2Cu(OH)2s" | chemeqwill display informations about the reaction of hydroxyde
and Cu II ions.
echo "MnO4^- + 8H3O^+ + 5e- --> Mn^2+ + 12 H2O" | chemeq
will display informations about the reaction of reduction
of permanganate ions in an acid environment.
echo "MnO4^- + 8H3O^+ + 5e- --> Mn^2+ + 12 H2O" | chemeq -w
will display the LaTeX format for the Nernst law related
to the reduction of permanganate ions in an acid environment.
echo "MnO4^- + 8H3O^+ + 5e- --> Mn^2+ + 8 H2O" | chemeq -c
will highlight the lack of conservation of elements H and
O (water molecules are not well balanced).
NOTES¶
syntax of ionsallthough in some cases, shorter expressions are
sucessfully parsed, it is safer to consider that an "up arrow" (^)
must be put before the charge symbols of an ion. Examples : H3O^+, Fe(CN)6^4-,
OH^-
Composing chemical equations
Two operators are defined, # as an additive oprator and ~
(tilde) as a substractive operator: they allow to compose several chemical
equations
echo "MnO4^- + 8H3O^+ + 5e- --> Mn^2+ + 8 H2O ~ 5Fe^3+ + 5e- ->
5Fe^2+" | chemeq
will display the pure redox equation from the first equation, minus the second
one. Electrons are simplified. So it will be equivalent to:
echo "MnO4^- + 8H3O^+ + 5Fe^2+--> Mn^2+ + 8 H2O + 5Fe^3+" |
chemeq which is their combination.
Mutiplying a chemical equation by one coefficient
The operator * permits to multiply a whole equation by
one coefficient which may be a fraction. Here is an example:
echo "5 * Fe^3+ + e- -> Fe^2+" | chemeq
will be equivalent to
echo "5Fe^3+ + 5e- -> 5Fe^2+" | chemeq
Combining chemical equations, with coefficients
The two previous techniques can be used at the same time,
which enables you to make more comlicated combinations, like this one:
echo "Fe^3+ + e^- -> Fe^2+ (0.77 V) # Fe^2+ + 6CN^- -> Fe(CN)6^4-
(Kfa=1e24) ~ Fe^3+ + 6CN^- -> Fe(CN)6^3- (Kfb=1e31)" | chemeq
which will work as expected, and yeld a good value for the stan‐ dard
potential of the redox couple of hexacyanoferrate II and III ions.
KNOWN BUGS¶
When not specified, chemical entities coming from the standard input are believed to be in aqueous solutions. Water is considered by default as the main solvent. Only one liquid (aqueous) phase is currently taken in account. All solid chemical entities are considered as parts of separated phases. Suffixes _s, _g and _aq can be used to enforce the type of some chemical entities. There may be problemes when you write a standard potential with no decimal dot. For example, the entry Mn^2+ + 2e^- -> Mn_s (-1 V) would trigger an error. Then write Mn^2+ + 2e^- -> Mn_s (-1.0 V) or the more accurate value Mn^2+ + 2e^- -> Mn_s (-1.18 V) and there will be no error.AUTHOR¶
Georges Khaznadar <georgesk@debian.org>Wrote this manpage.
COPYRIGHT¶
Copyright © 2000-2013 Georges Khaznadar06/19/2013 | chemeq 2.10 |