Energy formation enthalpy initial

Thus, the molar enthalpy of reaction (A//" ) is computed from the difference between the molar weighted reactant and product formation enthalpies. Note that enthalpy changes (like all energy changes) are computed in the form of final state -initial state, or in other words, products - reactants. 

The dependences of dissociation energy of binary molecules and formation enthalpies of single-atom gases upon initial spatial-energy characteristics of free atoms have been determined. 

In order to think constructively about these problems we need some scale on which we can measure that intrinsic property of the ions which determines (in part) both stability and reactivity. In practice, we have to content ourselves, as far as carbenium ions are concerned, with the gas-phase standard enthalpy of formation, AHf, of a series of ions, and make estimates of the effects of solvation energies. In this way we can go quite a long way towards rationalising the reactivity of initiating ions with various monomers. 

In the bomb process, reactants at the initial pressure pi and temperature 7 are converted to products at the final pressure pf and temperature Tf. The primary goal of a combustion calorimetric experiment, however, is to obtain the change of internal energy, Ac//°(7r), associated with the reaction under study, with all reactants and products in their standard states pi = pf = O.IMPa) and under isothermal conditions at a reference temperature 7r (usually 298.15 K). Once AC//°(298.15K) is known, it is possible to derive the standard enthalpy of combustion, AC77°(298.15K), and subsequently calculate the standard enthalpy of formation of the compound of interest from the known standard enthalpies of formation of the products and other reactants. 

The thermochemical characteristics of l,3,5-trinitro-l,3,5-triazepane, such as energies of dissociation of N-NOz bonds, enthalpies of formation, vaporization, and combustion, as well as enthalpy of formation of amine radicals, have been determined <2004MI92>. The rate constants of initial monomolecular stages of thermal decomposition in the solid phase were measured for its furazano-fused analog 20 <1999RCB1250> and the ratio of the rate constants of decomposition in the melt and solid states, characterizing the reaction retardation in the crystal lattice, was determined. The kinetics of the thermal decomposition of 20 has also been studied <1995MI885>. 

Therefore the main computational method for determining the values of chemical bond energy is the use of corresponding thermal-chemical values (enthalpies of formation of reaction products and initial molecule). 

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