Consider the reaction `N_2 + 3H_2 to 2NH_3`, taking place at `300K` temperature and constant pressure. For the reaction, `DeltaH = -22.0 kcal`. Calculate the amount of heat released if the reaction is carried out at `400K` and same constant pressure. Given that: `C_(p(N_(2)))=C_(p(H_(2)))=3.5 R, C_(p(NH_(3)))=4R`

Explanation

`N_(2(g))+3H_(2(g))to2NH_(3(g))`
From Kirchhoff's equation.
`DeltaH_(400)-DeltaH_(300)=DeltaC_(P)(T_(2)-T_(1))`
or `C_(P)=[2xxC_(P(NH_(3)))-(C_(P(N_(2)))+3xxC_(P(H_(2))))]`
`=[2xx4R-(3.5R+3xx3.5R)]-6R`
`:. DeltaH_(400)-(-22)=-6xxR(400-300)`
or `DeltaH_(400)+22=-6xx2xx10^(-3)xx100`
or `DeltaH_(400)=-1.2-22=-23.2 kcal`