Considering the following reactions, what type of reaction is represented by these two examples?

Mg(s) + 1/2 O_2(g) -> MGO(s) + 146Mg(s)+12O2(g)MGO(s)+146 kcal/mol
H_2(g) + 1/2 O_2(g) -> H_2O(g)H2(g)+12O2(g)H2O(g) DeltaH = -57.82 kcal/mol.

1 Answer
Jul 7, 2016

These are both "enthalpies of formation", DeltaH_f^@

Explanation:

The "enthalpy of formation" is the enthalpy associated with the formation of one mole of product from its constituent elements under standard conditions.

Note that you have listed enthalpy as a product in the formation of MgO; of course you are aware that this represents a NEGATIVE DeltaH_f^@. If you ar not clear on why I should mention this, ask for clarification.