In: Chemistry
For a particular isomer of C8H18, the combustion reaction produces 5104.1 kJ of heat per mole of C8H18(g)
consumed, under standard conditions.
C8H18(g)+252O2(g)⟶8CO2(g)+9H2O(g)Δ?∘rxn=−5104.1 kJ/mol
What is the standard enthalpy of formation of this isomer of C8H18(g)?
Given:
ΔHo rxn = -5104.1 KJ/mol
Hof(O2(g)) = 0.0 KJ/mol
Hof(CO2(g)) = -393.509 KJ/mol
Hof(H2O(g)) = -241.818 KJ/mol
Balanced chemical equation is:
C8H18(g) + 25/2 O2(g) ---> 8 CO2(g) + 9 H2O(g)
ΔHo rxn = 8*Hof(CO2(g)) + 9*Hof(H2O(g)) - 1*Hof( C8H18(g)) - 25/2*Hof(O2(g))
-5104.1 = 8*(-393.509) + 9*(-241.818) - 1*Hof(C8H18(g)) - 25/2*(0.0)
Hof(C8H18(g)) = -220.334 KJ/mol
Answer: -220.334 KJ/mol