Use the Following Data to Calculate the Standard Heat (Enthalpy)

Multiple Choice

Use the following data to calculate the standard heat (enthalpy) of formation, ΔH_f°, of manganese(IV) oxide, MnO₂ (s) . 2MnO₂(s) → 2MnO(s) + O₂(g) ΔH = 264 kJ
MnO₂(s) + Mn(s) → 2MnO(s) ΔH = −240 kJ

A) −504 kJ
B) −372 kJ
C) −24 kJ
D) 24 kJ
E) 504 kJ