[Metamorphose]

When 2 mol of SO2 reacts completely with 1 mol of O2 to form 2 mol of SO3 at 25 C and at a constant pressure of 1 atm, 198 kJ of energy is released as heat. Calculate delta H and delta E for this process.


The way I answered it was:

2SO2 + O2 ---> 2SO3

Because it is at constant pressure, DeltaH = q_p = -198 kJ

Delta E = Delta H - PdV = Delta H - nRT

= -198kJ -(-1 mol)(8.314Jmol^-1K^-1)(298K)
= -198,000 J + 2480 J
= -1.96 x 10⁵ J

Is this correct?

[ramboacid]

I'd like to think so. You chose that  :delta: H = -198 kJ rather than  :delta: E because the heat released was calculated under constant pressure, not constant volume. Your formulas and constants are also correct as far as I can see.

Maybe, as you data was given in kJ, you should report your answer in kJ as well.