Calculate the enthalpy change for the reaction
`H_2(g) + 1/2 O_2(g) to H_2O (g)`
if the bond energies of `H - H,O = O and O - H` bonds are 104, 118 and 11 kcal mol^(-1)` respectivley.

Explanation

To calculate the enthalpy change (ΔH) for the reaction:

\[ H_2(g) + \frac{1}{2} O_2(g) \rightarrow H_2O(g) \]

we will use the bond energies provided for the bonds involved in the reaction. The bond energies are:

- Bond energy of \( H-H \) = 104 kcal/mol
- Bond energy of \( O=O \) = 118 kcal/mol
...