Reaction Equation ΔHrxn (kJ/mol)
1 MgO(s) + 2 HCl(aq) ⟶ MgCl2(aq) + H2O(l) -192.295
2 Mg (s) + 2 HCl(aq) ⟶ MgCl2(aq + H2(g) -509.444
3 …show more content…
It can be calculated y subtracting the sum of enthalpies of formation of reactants from the sum of enthalpies of formation of the products. The enthalpy of formation is the ΔHrxn when 1 mole of a compound is formed from its elements in their standard states at 25℃ at 1 atm.2 The change in enthalpy per mole of a reaction was illustrated by part B of the experiment, because the change in enthalpy per mole of HCl or NH4OH was calculated. The standard molar enthalpy of formation was illustrated by part C of this experiment, because the various reactions added up to a reaction that led to the creation of 1 mole MgO from its elements at their standard states. Hence, the ΔHrxn in this reaction represented the enthalpy of