CCL: Question: arrhenius parameters with MOPAC
- From: "Carlos Abraham Diaz"
- Subject: CCL: Question: arrhenius parameters with MOPAC
- Date: Tue, 4 Nov 2008 16:19:48 -0500
Sent to CCL by: "Carlos Abraham Diaz" [cancerbero_85|hotmail.com]
Hello. I need some help in the determination of the activation energy of this
NH3 + H3PO4 ------> NH4H2PO4 + H2O
ammonia phosphoric acid ammonium phosphate water
It's a neutralization and exothermic reaction. And however a fast raction rate
(i can't measure with standard equipment) I assume that is a elementary
My questions are:
IT'S POSSIBLE CALCULATE THE Ea WITH MOPAC IN A NORMAL PC?
THERE IS NOT EXPERIMENTAL DATA ABOUT THIS REACTION?
I have the heats of formation of reagents and products and i tried the
Ea = E* + BHf
And i found for a exothermic reaction that
Ea = 40 + 0.25Hf
But the result is a negative Ea.
I don't have so much knowledge in computational chemistry and i only need the
numeric valor of the Ea and/or the reference.
Carlos Abraham Diaz
Ciudad Obregon, Sonora, Mexico.