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Calculate |Delta_(f)G^(@)| for (NH_(4)Cl, s) at 350 K. Given : Delta_(f)H^(@) (NH_(4)Cl, s)=-314.5" kJ/mol" {:(S_(N_(2)(g))^(@)=192 JK^(-1) mol^(-1),,S_(H_(2)(g))^(@)=130.5 JK^(-1) mol^(-1),),(S_(Cl_(2)(g))^(@)=223 JK^(-1) mol^(-1),,S_(NH_(4)Cl(s))^(@)=94.5 JK^(-1) mol^(-1),,"All given data at 300 K".),(Delta_(r)C_(P)=-20" J/mol-K",,ln(350/300)=0.15,):} |
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Answer» <P> Solution :`Delta_(f)S^(@)(NH_(4)Cl, s)` at `300 K=S_(NH_(4)Cl(s))^(@)-[1/2 S_(N_(2))^(@)+2S_(H_(2))+1/2 S_(Cl_(2))^(@)]``=94.5-(1/2xx192+2xx130.5+1/2xx223)` `=94.5-(96+261+111.5)` `Delta_(f)S_(300)^(@)""=-374 JK^(-1) mol^(-1)` `Delta_(f)S_(310)^(@)""=Delta_(f)S_(300)^(@)+Delta_(r)C_(p)ln (350/300)` `=-374-20xx(0.15)=-377 JK^(-1) mol^(-1)` `Delta_(f)H_(310)^(@)""=Delta_(f)H_(300)^(@)+Delta_(r)C_(p) [350-300]` `=-314.5-(20xx50)/(1000)=-315.5` `Delta_(f) G_(350)^(@)""=Delta_(f)H^(@)-T. Delta_(f) S^(@)` `=-315.5-(350xx(-377))/(1000) ""rArr-183.55" kJ/mol"` `|Delta_(f) G_(350)^(@)|""=183.55" kJ/mol"rArr""183" kJ/mol"` |
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