A first-order homogeneous liquid-phase reaction ( $\mathrm{A} \rightarrow \mathrm{B}$ ) occurs in an adiabatic, ideal mixed flow reactor operating at steady state. The volumetric flow rate of the feed is $4 \mathrm{~L} \mathrm{~min}^{-1}$ and volume of the reactor is $20$ $\text{L}$. At the reactor temperature of $500 ~\text{K},$ the reaction rate constant is $1 \mathrm{~min}^{-1}$, and heat of reaction is $-20 ~\mathrm{kcal} ~\mathrm{mol}{ }^{-1}$. The average heat capacity of the feed as well as the reaction mixture in the temperature range of interest is $0.3 ~\mathrm{kcal} ~\mathrm{mol}^{-1} \mathrm{~K}^{-1}$.
At the inlet, the feed temperature (in $\text{K}$) is $\_\_\_\_$ (rounded off to one decimal place).
