Thermochemical Equation
A balanced chemical equation that also states the enthalpy change for the amounts shown.
Formula / equation
aA + bB → cC, ΔH = x kJ
Unit
kJ/mol
In depth
Because the quoted enthalpy applies to the exact molar amounts written, doubling the coefficients doubles ΔH, and reversing the equation reverses its sign. State symbols are essential, since the enthalpy change differs substantially depending on the physical state of each species.
Examples in the real world
H₂(g) + ½O₂(g) → H₂O(l), ΔH = −286 kJ; forming steam instead releases only 242 kJ.