Using the information below, calculate ΔH°_f for C₂H₅OH(l) .C₂H₅OH(l) + 3O₂(g) → 2CO₂(g) + 3H₂O(l) , ΔH° = -1367 kJ
ΔH°_f for CO₂(g) = -393.5 kJ/mol
ΔH°_f for H₂O(l) = -286 kJ/mol

Question

Quizplus · Accepted Answer

To find ΔH°f for C2H5OH(l), use the equation for the reaction's enthalpy change: ΔH° = ΣΔH°f(products) - ΣΔH°f(reactants). For the products, 2 mol of CO2(g) and 3 mol of H2O(l) contribute -393.5 kJ/mol * 2 + -286 kJ/mol * 3 = -1645 kJ. The only reactant with an unknown ΔH°f is C2H5OH(l), and O2(g) is a standard state element with ΔH°f = 0. Rearranging the equation gives ΔH°f(C2H5OH) = ΣΔH°f(products) - ΔH° - ΣΔH°f(reactants excluding C2H5OH). Substituting the given values yields ΔH°f(C2H5OH) = -1645 kJ - (-1367 kJ) = -278 kJ/mol.

Using the Information Below, Calculate ΔH°f for C2H5OH(l)

Using the Information Below, Calculate ΔH°_f for C₂H₅OH(l)