The standard enthalpy of formation of `H_(2)(g)` and `Cl_(2)(g)` and `HCl(g)` are `218 kJ//mol`, `121.88 kJ//mol` and `-93.31 kJ//mol` respectively. Calculate standard enthalpy change in `kJ` for
`(1)/(2)H_(2)(g)+(1)/(2)Cl_(2)(g)toHCl(g)`

The standard enthalpies of formation of HCl(g), H(g) and Cl(g) are -92.2 , 217.7 and 121.4 kJ mol^(-1) respectively. The bond dissociation enthalpy of HCl is :

If the standard molar enthalpy of formation of SO _(2 (g)) and SO _(3(g)) is - 296 . 82 kJ mol ^(-1) and -395 . 72 kJ mol ^(-1) respectively, then enthalpy change for the reaction in kJ mol ^(-1) , SO _(2 (g)) + (1)/(2) O _(2 (g)) to SO _(3(g)) , is

DeltaH_(t)^(@) for CO_(2)(g) and H_(2)O(g) are -393.5, -110.5 and -241.8 kJ"mol"^(-1) respectively. The standard enthalpy change (in kJ) for the reaction. CO_(2)(g) + H_(2)(g) to CO(g) + H_(2)O(g) is:

a) The enthalpy of combustion of CH_(4(g)), C_(graphite) and H_(2(g)) at 298 K are - 890.3 kJ mol^-1 , - 393.5 kJ mol^-1 and -285.8 kJ mol^-1 respectively. Calculate the enthalpy of formation of CH_(4(g)).

Calculate enthalpy of formation of HCl if Bond enthalpies of H_2, Cl_2 and HCl are 434 kJ mol^(-1) , 242 kJ mo l^(-1) and 431 kJ mol^(-1) respectively.