For the reaction
`N_(2)+2O_(2)to2NO_(2)`
Given : at 1 atm, 300 K
`S_(N_(2))=180J//mol//K`
`C_(p)(N_(2))=30J//mol//K`
`S_(O_(2))=220J//mol//K`
`C_(p)(O_(2))=30J//mol//K`
`S_(NO_(2))=240J//mol//K`
`C_(p)(NO_(2))=40J//mol//K`
Calculate
(i) `DeltaS_(300K,1"atm")`
(ii) `DeltaS_(400K,1"atm")`
(iii) `DeltaS_(300K,5"atm")`
(iv) `DeltaS_(400K,5"atm")`

Explanation

(i) `(DeltaS_(r))_(300)=2S_(NO_(2))-2S_(O_(2))-S_(N_(2))`
`=2xx240-2xx220-180`
= `-140Jmol^(-1)k^(-1)`
`(DeltaCp)_(r)=2Cp(NO_(2))-2Cp(O_(2))-Cp(N_(2))`
= `2xx40-2xx30-30`
`=-10Jmol^(-1)k^(-1)`
(ii) `(DeltaS_(r))_(400)=(DeltaS_(r))_(300)+(DeltaC_(p))_(r)//nT_(2)/T_(1)`
= `-140-10//n4/3`
`=-142.88Jmol^(-1)k^(-1)`
(iii) `(DeltaS_(r))_(300k,5"atm")=(DeltaS_(r))_(300k,1"atm")+Deltan_(g)R//n`
`p_(1)/p_(2)=-140+(-1)R//n1/5=-140+R//n5`
= `-140+8.314//n5`
= `-126.62 J mol^(-1)k^(-1)`
(iv) `(DeltaS_(r))_(400k,5"atm")=(DeltaS_(r))_(400k,"1atm")-R//n1/5`
= `142.88+R//n5`
= `-129.5Jmol^(-1)k^(-1)`