Calculate the enthalpy (ΔHo) of reaction (kJ) for the equation as written. If the answer is negative, enter the sign and then the magnitude.
2 HCOOH(l) + O2(g) → 2 CO2(g) + 2 H2O(l) .
ΔHof (kJ/mol)
HCOOH(l) -409
O2(g) 0
CO2(g) -393.5
H2O(l) -285.83
the answer is 501.7...how do you come to this??