Heat transfer in solids coupled with Transport of diluted species

Hi,

I'm trying to couple heat transfer in solids with transport of diluted species.

Reaction rate R = -Ca* (A*exp(-E/RT))

I want to impose temperature constraint on this reaction. I want the reaction to be happen only between the temperature range of 500-580K.

I'm using R = -(Ca* (A*exp(-E/RT)))*(500<T<580)

Heat Source Q = heat of reaction*chds.R

Also, heat should release whenever there is temperature of 500-580K because of the reaction and there should be no heat release after reactant convert to the products even the temperature is between 500-580K.

Please let me know where i'm doing wrong.

Thanks in Advance
Krish