The standard heat of formation of `U_(3)O_(8)` is -853.5 kcl//mol and the standard heat of the reaction `3UO_(2) +O_(2) rarr U_(3)O_(8)` is -76.01 Kcal.
The standard heat of formation of `UO_(2)` is

Options

A. `-1083KJmol^(-1)`
B. `-108.3KJmol^(-1)`
C. `-10.83KJmol^(-1)`
D. `-1.083KJmol^(-1)`

Answer

C

Explanation

`3U O_(2) + O_(2) rarr U_(3)O_(8)`
`Delta H^(@) = Delta H_(f)^(@) (U_(3)O_(8)) - Delta H_(f)^(@) (O_(2)) - 3 Delta H_(f)^(@) (U O_(2))`
`implies 3DeltaH_(f)^(@) (UO_(2))=-DeltaH^(@) + DeltaH_(f)^(@)(U_(3)O_(8)) - DeltaH_(f)^(@)(O_(2))`
or `Delta H_(f)^(@) (UO_(2)) = (-(-76.0) + (-583.5)-0)/(3)`
`=-259.17` Kcal
`=-1083.33` KJ/mol