Spartan’s T1 method adapts the G3(MP2) recipe to calculate this quantity. For compounds that are hard to synthesize, this quantity is estimated using a connectivity-based hierarchy or by comparing against an isodesmic reaction. This quantity decreases by 5 of its usual units for each methylene (-5[1])in a hydrocarbon in Benson’s group addition method. NIST’s JANAF database tabulates this quantity for more than (-5[1])4000 compounds at (*) 298 Kelvin. This quantity is the sum of steps for sublimation, ionization, electron affinity, and lattice energy in a Born-Haber cycle, (-5[1])and it equals zero for graphite at standard state. (-5[1])The energy evolved (10[1])by a reaction at constant pressure equals this quantity for products minus reactants. (-5[1])For 10 points, name this energy required to build a molecule from pure (10[2])elements. ■END■ (10[5]0[6])