Answer to Question #205333 in General Chemistry for lea

Question

Propane (C3H8) burns according to the following balanced equation: C3H8(g)+5O2(g)→3CO2(g)+4H2O(g) Part A Calculate ΔH∘rxn for this reaction using standard enthalpies of formation. (The standard enthalpy of formation of gaseous propane is -103.9 kJ/mol .) Express the enthalpy in kilojoules to four significant figures.

Answer 1

$DeltaH^0rxn = \Delta H^0f products - \Delta H^0f reactants$

$\Delta H^0rxn = [4 (-241.8) + 3 (-393.5)] - [-103.9]$

$\Delta H0rxn = [-967.2 - 1180.5] + 103.9$

$\Delta H^0rxn = - 2043.8 KJ/mol$