We need to calculate the heat produced by a set of $\mathrm{N_R}$ reactions in our reactor model.
\begin{align} \mathrm{Q_r = \sum_{j=1}^{Nr} Rr_j*\Delta H_{R,j}} \end{align}
$\mathrm{Rr_j}$ is the reaction rate of reaction $\mathrm{j}$, in $\mathrm{\frac{kmol}{kg_{cat} s}}$
$\mathrm{\Delta H_{R,j}}$, in $\mathrm{\frac{kJ}{kmol}}$, is constant and calculated as:
\begin{align} \mathrm{\Delta H_{R,j} = \sum_{i=1}^{Nc}\nu_{i,j}*\Delta h_{i,j}^f} \end{align}
Now consider these: \begin{align} \mathrm{R1:}\ \ce{H2 + 1/2O2 \rightarrow H_2O} \end{align} \begin{align} \mathrm{R2:}\ \ce{2H2 + O2 \rightarrow 2H_2O} \end{align}
They are undoubtedly the same reaction, but the R2 gives a $\mathrm{\Delta H_R}$ that is twice the $\mathrm{\Delta H_R}$ in R1. It is naturally so, but greatly affects my energy balance.
How do I know which is the "correct" way to write the reaction?
Does it mean that the reaction rate should be specific to R1 or R2?