Answer:
562.76 kJ
Explanation:
∆H° (kJ) is the total of the heats of formation of the products minus the total of the heats of formation of the reactants.
NB: look up the heats of formation of the compounds in the heats of formation reference tables, it is found at the back of most chemistry text
heats of formation of the products (i.e. Fe₃O₄(s) , 6HCl(g) , H₂(g) ) = -1120.9 + 6(-92.3)+ 0 = -1674.7 kJ
heats of formation of the reactants (i.e. 3FeCl₂(s) , 4H₂O(g) ) =3(-423.42) + 4(-241.8) = -2237.46kJ
∆H° = -1674.7 kJ - (-2237.46kJ) =562.76 kJ
