Chapter 6, Problem 6.147QP

The head of a “strike anywhere” match contains tetraphosphorus trisulfide, P₄S₃. In an experiment, a student burned this compound in an excess of oxygen and found that it evolved 3651 kJ of heat per mole of P₄S₃ at a constant pressure of 1 atm. She wrote the following thermochemical equation:

$\begin{array}{c}{\text{P}}_4{\text{S}}_3(s)+8{\text{O}}_2(g)\to {\text{P}}_4{\text{O}}_{10}(s)+3{\text{SO}}_2(g);\\ \Delta H°=-3651\text{kJ}\end{array}$

Calculate the standard enthalpy of formation of P₄S₃, using this student’s result and the following standard enthalpies of formation: P₄O₁₀(s), −3009.9 kJ/mol; SO₂(g), −296.8 kJ/mol. How does this value compare with the value given in Appendix C?