LaurenDinh_3L
Posts: 23
Joined: Fri Sep 26, 2014 2:02 pm

For a problem like 7.63, why do we need to write out all of the equations of the reactants and products? Why can't we simply use the equation: delta H rxn = sum(delta H products) - sum(delta H reactants)?

Krista 3L
Posts: 10
Joined: Fri Sep 26, 2014 2:02 pm

Krista Lum 3L

delta H rxn = sum(delta H products) - sum(delta H reactants) equation is used for the standard enthalpy formation method of determining delta H of the reaction. To solve this problem with the information given, you need to use Hess's Law in which you write out how you get the equation you need from the ones given to get credit.

Regina Chi 2K
Posts: 51
Joined: Fri Sep 26, 2014 2:02 pm

Regardless of getting "credit" or not, I was wondering how we would know what to include in each of the steps? For example, how would we know which elements to use, what compounds are formed, and how many steps it will take?

Neil DSilva 1L
Posts: 70
Joined: Fri Sep 26, 2014 2:02 pm