The question asks to predict the signs of ∆H and ∆S for the reaction 2O(g)->O2(g)
first, I'm not sure how to "predict" ∆H; I looked the ∆Hformations in the back of the book and calculated it using the heat of formation of the products minus that of the reactants. I get -249 kj/mol. How would I "predict" the sign of ∆H?
second, I'm running into a contradiction for ∆S: this reaction has decreasing positional probability; i.e. 2 molecules to 1 molecule, and thus ∆S should be negative. However, according to the equation ∑Sreaction=∑Sproducts - ∑Sreactants, ∆S for the reaction is actually positive: 205.41 - 161= 44 J/Kmol. Which sign is right?
Thank you for the help.