Question

I've figured out the Ea but I'm not sure how to find the kcal/mol

The gas reaction N2O5 → 2NO2 + 1/2O2 follows the Arrhenius equation k = Ae(-Ea/RT) where R = 8.314 J K-1 mol-1 and 1 calorie = 4.184J. At the temperature T=273K, k = 3.46 x 10-5 s-1, whereas at T = 298K, k = 8.87 x 10-3 s-1. What is the value of the activation energy Ea in kJ/mol and in kcal/mol. What is the rate constant at 100 oC?
ln(3.46 x10-5 s-1)/(8.87 x 10-3 s-1)=Ea/(8.314 J/(K.mol))(1/(298 K)-1/273k)
Ea= 1.50 x 105 J or 150 kJ

Answer 1

150 kJ is correct.

Answer 2

I need to know the kcal/mol. How do I find the kcal/mol??

Answer 3

1 cal = 4.184 J.
1 kcal = 4.184 kJ