Formation Equations
In a formation equation, 1 mol of a compound forms from its
elements. The standard heat of formation (DHof) is the enthalpy
change for the formation equation when all substances are
in their standard states.
C(graphite) + 2H2(g) CH4(g) DHof = -74.9 kJ
An element in its standard state is assigned a DHof of 0.
Most compounds have a negative DHof (i.e., the compound
is more stable than its component elements).
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