This problem is providing us with the chemical equation for the formation of water from hydrogen and oxygen, and asks for the enthalpy change via bond energies. At the end, one finds it as -509kJ/mol kJ.
Bond energies:
In chemistry, bond energies are defined as the necessary energy to break a bond between two atoms. In this case, we see that water, H₂O has two H-O bonds and hydrogen (H₂) and oxygen (O₂) have one H-H and one O=O bonds, respectively.
Thus, we write the following heat equation, which comprises the aforementioned bond energies and the stoichiometric coefficients in the reaction:
[tex]\Delta H=2*(\Delta H_{H-H})+1*(\Delta H_{O-O})-2*(2*\Delta H_{H-O})[/tex]
Hence, we plug in the reported bond energies to obtain:
[tex]\Delta H=2*(432kJ/mol)+1*(495 kJ/mol)-2*(2*467kJ/mol)\\\\\Delta H=-509kJ/mol[/tex]
Learn more about bond energies: brainly.com/question/26141360
