Question

For the reaction:
`2H_(2)(g) +O_(2)(g) rarr 2H_(2)O(g), DeltaH =- 571 kJ`
bond enegry of `(H-H) = 435 kJ` and of `(O=O) = 498 kJ`. Then, calculate the average bond enegry of `(O-H)` bond using the above data.
A. 484 kJ
B. `-484kJ`
C. `271kJ`
D. `-271kJ`

Answer 1

Correct Answer - A
`2(H-H)+O=Oto2(H-O-H)`
`DeltaH=sum(BE)_("reactants")-sum(BE)_("products")`
`=571=[2xx435+498]-4xx(BE)_(O-H)`
`(BE)_(O-H)=(2xx435+498+571)/(4)=~~484kJ`