Answer:
1) -572 kJ/mol
2) -2220.7 kJ/mol
Step-by-step explanation:
Multiply the bond enthalpies to take into account the amount of moles of each compound in the reaction. Then, to get the total change in energy/enthalpy in the reaction, subtract the reactant energy from the product energy.
1) 2(-286) = -572 kJ/mol
2) 4(-286) + -393.5(3) - -103.8 = -2220.7 kJ/mol