@Carl Love 

Thanks for the reply. To clarify:

• T is supposed to be in the denominator
• I realised this second point after having posted this question

However would it be possible to solve using a set of initial conditions that were not equal? Also if I do get a numerical solution would it be at a single point on the curve or at several points which I could then use to plot a graph. I'm thinking I could then use this to get an estimate for the expressions of Cno and Cnh3, perhaps using a curve fitting tool

thanks again for your help 

T is supposed to be in the denominator

I realised this second point after posting this question. However I would also like to solve for initial conditions that are not equal

Also, would a numeric solutioin give results at a single point or across a range of values. If so then i could then use these values to estimate a new expression for each of the concentrations (perhaps using a curve fitting tool)? I hope this makes sense.

Thanks again