1. What energy change is associated with the reaction to obtain one mole of H2 from one mole of water vapor? The balanced equation is 2 H2O(g) g 2H2(g) + O2(g) and the relevant bondenergies are: H-H = 436 kJ/mol; H-O = 467 kJ/mol; O-O = 146 kJ/mol O=O = 498 kJ/mol
A. -425 kJ
B. +425 kJ
C. -436 kJ
D. +249 kJ