Enthalpy of Reaction at other than 298K

juice34

I am curious as to how to calculate the heat of reaction for a exothermic chemical reaction other than at 298.15K. This is more of a check than anything else and anyone elses input on how to obtain more accurate results will be greatly appreciated. Here we go

I want to calculate the heat of reaction for a process at lets say 600K, although i have the known heat of reaction at 298K as well as the Cp at 298K.

Part A)
From what i know,
the new heat of reaction is=integral(Cp(298K), 298K,600K)=delta H at 600K [kj/mol], correct?

Part B)
although, i have found other references that have conflicting reports on the Cp to use, some say use the Cp at 600K, in the above equation, which i dont think makes sense?

Part C)
The logical way, if i know the Cp at 600K (calculated from the shomate), i can just multiply the Cp(600K)*T(600K), correct?

Part D)
As far as getting more accurate values, obtaining the residuals (by calculation of course) will give the best numerical value.(from an old thermo book)