Calculate the heat produced (in kJ) when 224 gm of CaO is completely converted to `CaCO_(3)` by reaction with `CO_(2)` at `27^(@)` in a container of fixed volume.
Given : `DeltaH_(f)^(@)(CaCO_(3),s)=-1207kJ//mol," "DeltaH_(f)^(@)(CaO,s)=-635kJ//mol`
`DeltaH_(f)^(@)(CO_(2),g)=-394kJ//mol,["Use R"=8.3JK^(-1)mol^(-1)]`

Options

A. `702.04` kJ
B. `721.96` kJ
C. 712 kJ
D. 721 kJ

Answer

A

Explanation

`CaO(s)+CO_(2)(g)rarrCaCO_(3)(s)`
`Delta_(f)H^(@)=DeltaH_(f)^(@)(CaCO_(3))-DeltaH_(f)^(@)(CaO)-DeltaH_(f)^(@)(CO_(2))`
`=-1207 -(-635)-(-394)`
=-178 kJ/mol
`thereforeDeltaU=DeltaH-Deltan_(g)RT`
`DeltaU=-178-((-1)xx8.3 xx300)/(1000)`
=-175.51 kJ
`n_(CaO)=(224)/(56)=4`
`thereforeq_(v)=n.Delta_(r)U=4xx(-175.51)`
=-702.04 kJ