simultaneous equations for chemical speciation

*To*: mathgroup at smc.vnet.net*Subject*: [mg100186] simultaneous equations for chemical speciation*From*: Jem & Tracy <jemandtracy at bigpond.com>*Date*: Wed, 27 May 2009 04:09:01 -0400 (EDT)

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 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) Sofar my formula looks like: 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}] If I use a similar formula for the "Eliminate" function, I get error mesages. 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