For a particular isomer of C8H18, the combustion reaction produces 5104.1 kJ of heat per mole of C8H18 consumed under standard conditions. Given that the standard enthalpies of formation for CO2(g) and H2O(l) are -393.5 kJ/mol and -285.8 kJ/mol respectively, what is the standard enthalpy of formation of this isomer of C8H18?

The oxidation of ammonia is illustrated by the following equation:

4 NH₃ (g) + 5 O₂ (g) → 4 NO (g) + 6 H₂O (g)

Calculate the enthalpy of reaction,ΔH_Rxn, based on the given standard heats of formation.

Consider the following equation:

2 ClF₃(g) + 2 NH₃(g) → 1 N₂(g) + 6 HF (g) + 6 Cl₂(g)ΔH_rxn = –1196 kJ

Determine the standard enthalpy of formation for chlorine trifluoride, ClF₃.

N₂ + 2 O₂ → 2 NO₂
Based on the following data.
2 NO → N₂ + O₂    ΔH = −180 kJ
2 NO + O₂ → 2 NO₂    ΔH = −112 kJ