C2H4(g)+3O2(g)→2CO2(g)+2H2O(l)
ΔU=−1406kJmol−1
T=300K
ΔH=ΔU+ΔngRT
ΔU is the change in the internal energy of the system, which is the sum of the kinetic and potential energies of all the molecules in the system. R is the gas constant (8.314J/(molK) and T is the temperature in Kelvin.
ΔH=–1406+(–2)×8.3×300=–1406–4.98=–1410.98KJmol–1≈–1411TheminimumvalueofTΔSatequilibriumΔHΔH=TΔS=–1411KJmol–1