It is also known that C4, C3, C2 and even C1 have heats of formation in the ideal gas phase at room temperature which are greater per carbon atom than that of C6. The heat of formation is a very useful quantity as it permits evaluation of the heat of reaction of any chemical process. However, it is a variable term which depends on the definitions of reference states. If we are bold enough and look at the notorious explosives we shall find that the heats of formation may be positive or negative. In fact, energy contents are not good predictors of explosive strength.
Conventional explosives have a lower energy output, by one order of magnitude, than common fuels.
Burning one gram of graphite or gasoline gives 33 and 47 kJ, respectively. Still, no one tries to use coal in place of dynamite, though porous charcoal with liquid oxygen or simply coal dust would work. However, the energy produced is essentially the same in all the three carbon species. Indeed, the time for complete reaction is shorter in explosions, by five orders of magnitude, than in the burning of fuel. Therefore, pressures developed are higher by four to six orders of magnitude.