Atomic Conservation in Ionized Hydrogen Gas

[Mr. Cosmos]

Dear all,
So I have a question concerning atomic conservation in an ionized hydrogen gas. So imagine we have $H_2$ initially. Later the gas is taken to an appreciable temperature such that at equilibrium the following species are present, $e^-, \ H, \ H^+, \ H_2, \ H^-, \ \text{and} \ H_2^+$. In order to properly minimize the Gibbs free energy for such a system I need to appropriately apply atomic conservation in the form,
$b_k = \sum_{i = 1}^n a_{i,k} \ y_i$
where $a_{i,k}$ is the number of atoms of component $k$ in species $i$, $b_k$ is the number moles of component $k$ per mass of mixture, $n$ is the total number of species, and $y_i$ is the number of moles of species $i$ per mass of the mixture. This is fairly simple when dealing with chemical systems that are not ionizing. However, I am confused about how to treat the atomic conservation in the case of ionized hydrogen. I am not entirely sure how to treat the electron and other ions, so that the conservation is consistent. Any help would be greatly appreciated.
Thanks.

 

[DrClaude]

In this case, I would take the "chemical species" to be protons and electrons, and write the conservation equations for p and e.