Given the following reactions
H2O (l) →H2O (g) ΔH = 44.01 kJ
2H2 (g) + O2 (g) → 2H2O (g) ΔH = -483.64 kJ
the enthalpy for the decomposition of liquid water into gaseous hydrogeand oxygen
2H2O (l) → 2H2 (g) + O2 (g)
is __________ kJ.
We’re being asked to determine the enthalpy change (ΔHrxn) for the chemical reaction:
2 H2O (l) → 2 H2 (g) + O2 (g)
We can use Hess’s Law to determine the enthalpy change of the overall reaction from the given reactions:
1. H2O (l) →H2O (g) ΔH1 = 44.01 kJ
2. 2H2 (g) + O2 (g) → 2H2O (g) ΔH2 = - 483.64 kJ
We now need to find a combination of reactions that when added up, gives us the overall reaction.