Calculate the heat of formation of methane inKcal "mol"^(-1) using the following thermo chemical reactions : C(s) + O_2 (g) to Ca_2 (g) "","" DeltaH = - 94.2 "Kcal mol"^(-1) H_2 (g) + 1/2 O_2(g) to H_2 O (l) "",""DeltaH = - 68.3 "kcalmol"^(-1) CH_4 (g) + 2O_2 (g) to CO_2 (g) + 2H_2 O (l)"", ""DeltaH=-210.8 "kcal mol"^(-1)

Calculate the heat of formation of methane inKcal "mol"^(-1) using the

1.	Calculate the heat of formation of methane inKcal "mol"^(-1) using the following thermo chemical reactions : C(s) + O_2 (g) to Ca_2 (g) "","" DeltaH = - 94.2 "Kcal mol"^(-1) H_2 (g) + 1/2 O_2(g) to H_2 O (l) "",""DeltaH = - 68.3 "kcalmol"^(-1) CH_4 (g) + 2O_2 (g) to CO_2 (g) + 2H_2 O (l)"", ""DeltaH=-210.8 "kcal mol"^(-1)
Answer» Solution :`C(s) + O_2 (g) to Ca_(2) (g) + 94.2 ` Kcal `""….(1)` `H_2 (g)+ 1/2O_2 (g) to H_2 O (l) + 68.3 kcal ""….(2)` `CH_4 (g) + 2O_2 (g) to CO_2(g) + 2H_2 (l) + 210.8 kcal ""….(3)` The required equation is `C(g) + 2H_2 (g) to CH_4 (g)` so, `DeltaH_f= Delta H_l + (2xx DeltaH_2) - Delta H_3 =-20 "kcal MOL"^(-1)`.