Kaplan FL 7 PS #25

[azor ahai]

---

Members do not see this ad.

Why do they count O2?

 

[Cawolf]

Because you have to break an O=O bond to form the product.

There are O=O bonds in the reactants but not in the products.

 

[azor ahai]

Because you have to break an O=O bond to form the product.

But isn't O2's enthalpy of formation = 0?

 

[Cawolf]

The passage doesn't provide enthalpies of formation, it provides bond dissociation energies.

dH = BDE broken - BDE formed

not

dH = dHf (products) - dHf (reactants)

 

[azor ahai]

The passage doesn't provide enthalpies of formation, it provides bond dissociation energies.

dH = BDE broken - BDE formed

not

dH = dHf (products) - dHf (reactants)

Oooooh. Thanks!