What is the standard enthalpy of formation? Explain it with example.

Explanation

Standard heat of formation of compound is defined as the heat change accompanying the formation of one mole of a compound for its constituent elements. All the substance being in their standard states (1 bar pressure and 208 K).
Standard enthalpy of formation of the substance is also called its standard enthalpy and denoted by `H^(theta)`. Standard enthalpies of free elements are taken to be zero e.g.
`C_(("graphite"))+O_(2)(g)to CO_(2)(g), DeltaH^(theta)=-393.5kJ`