$CH _{4}+2 O _{2} \rightarrow CO _{2}+2 H _{2} O (\Delta H =-891 kJ / mol)$
આપેલ : $\Delta H _{ f }{ }^\theta\left( Al _2 O _3\right)=-1700\,kJ\,mol ^{-1}$
$\Delta H _{ f }{ }^\theta\left( Fe _2 O _3\right)=-840\,kJ\,mol ^{-1}$
$Fe , Al$ અને $O$ નું મોલર દળ અનુક્રમે $56,27$ અને $16\,g\,mol ^{-1}$.
$2 A ( g ) \rightarrow A _{2}( g )$
$298\, K$ પર $\Delta U^ \ominus,=-20\, kJ\, mol ^{-1}, \Delta S \odot=-30\, J$$K ^{-1}\, mol ^{-1},$ પછી $\Delta G ^{\ominus}$ ........$J$ હશે?