p.s. // Re: Re: new to group - Chemical Equation

*To*: mathgroup at smc.vnet.net*Subject*: [mg100235] p.s. // Re: [mg100213] Re: [mg100175] new to group - Chemical Equation*From*: "Scot T. Martin" <smartin at seas.harvard.edu>*Date*: Thu, 28 May 2009 19:34:54 -0400 (EDT)*References*: <6147782.1243412890107.JavaMail.root@n11> <200905280829.EAA14200@smc.vnet.net>

Jem, I will just add that the solution to chemical equilibrium equations involves a constrained matrix of log-linear combinations. Typically, the approach is a numerical solution, using on of the advanced minimization functions like a simplex algorithm (although I am not a mathematician so others on this site may have more developed opinions than mine of "forget analytical solutions and go for a numerical solution"). Simplex is available as the method "NelderMead" of the NMinimize[] function. On Thu, 28 May 2009, Scot T. Martin wrote: > Jem, > > I'm a chemist, and I have various thermodynamic and kinetic solvers. Here's > one that could do what you want. It's from April 1999, but it should still > work fine (though I haven't tested it): > > http://www.seas.harvard.edu/~smartin/surface complexation model.nb > > This program does more than you want, i.e., the equilibrium equations include > a term for adsorption to a surface. Nevertheless, maybe you'll find the > package helpful for your application. > > Best, Scot > > >> From: Jem > [mailto:not.a.ninja25 at gmail.com] > >> Hi, >> >> Hi, I am a postgrad student and completely new to mathematica, I am just >> starting to realise the possibilities. >> >> I am trying to do a chemical speciation calculation. >> I have a set of simultaneous equations which represents the equilibria, >> mass >> balance, and charge balance in the system. >> >> I want to eliminate some of the variables, and then be able to solve for >> the >> remaining ones. >> My system of equations looks like this: >> a=b+c+d >> e=f+g+c+2d >> h=c/(bg) >> i=d/(cg) >> hi=d/(bg^2) >> j=mg/f >> k=lm >> n+m+b+c=g+l >> >> I will try to attach an image of what my formula looks like sofar. >> Basically, I can solve for the variable I want, but I am having trouble >> eliminating the ones I don't want (ie. I am getting an answer that is in >> terms of the wrong variables) >> >> I have been in the help files for ages, and don't really understand how to >> do this. >> I would really appreciate some pointers!! >> Thanks >> >> >> Solve[{a == b + c + d, e == f + g + c + 2 d, h == c/(b*g), >> i == d/(c*g), h*i == d/(b*g^2), j == m*g/f, k == l*m, >> n + m + b + c == g + l}, {g}] >> >> >> >> >> >

**References**:**Re: new to group - Chemical Equation Solutions***From:*"David Park" <djmpark@comcast.net>