Calculate the heat of reaction (kJ/mol) for the following reaction from the listed standard enthalpies of formation:

Question

Calculate the heat of reaction (kJ/mol) for the following reaction from the listed standard enthalpies of formation:

 

P₄O₁₀(s) + 6 H₂O(l) → 4 H₃PO₄(aq)

 

ΔH_f° of P₄O₁₀(s) = -2984.0 kJ/mol

ΔH_f° of H₂O(l) = -285.8 kJ/mol

ΔH_f° of H₃PO₄(aq) = -1277.4 kJ/mol

Answer 1

∑products - ∑reactants

∑products = 4 x -1277.4 = -5109.6 kJ

∑reactants = -2984 + 6 x -285.8 = -4698.8

∆Hrxn = ∑products - ∑reactants = -5109.6 kJ - (-4698.8)

∆Hrxn = -410.8 kJ