Enthalpy of explosion

Therefore, the enthalpy of explosion (AHex) for TNT corresponds to the reaction enthalpy for the following reaction ... 

Berthelot and Vieille (4) determined the difference between the enthalpy of explosion of ammonium picrate and that of an... 

Mass effects due to some ions in salts. It is generally observed that there is a greater instability amongst compounds containing heavy atoms compared with elements in the first periods of the periodic tabie.This can be observed by analysing enthalpies of formation of ammonia, phosphine, arsine and stibine (see previous table for the last three). In the same way, it is easier to handle sodium azide than lead azide, which is a primary explosive for detonators. It is exactly the same with the relatively highly stable zinc and cadmium thiocyanates and the much less stable mercury thiocyanate. 

Besides, the fact that depends on the - AH j difference makes the case for a general property for explosives not possible (in the case of a weak C ) or limited (in the case of a medium Ci). This effect emphasises the importance on stability of a small difference between enthalpies of combustion and degradation. 

The enthalpy of decomposition, which is rather low compared with criterion C, in the CHETAH programme (see p.117), was determined by DSC and corresponds to 0.76 KJ/g at 230-260°C. In a confined atmosphere the decomposition conditions would be explosive. This reaction has been used many times because of its spectacular aspect. This is why it is called Vesuvius fire by artificers and green volcano by lecturers. These demonstrations should be stopped because of the detonation risks they represent as well as chromium (III) oxide toxicity. 

Thus in hydrochloric acid medium, potassium hexacyanoferrate (111) is thought to give cyanoferric acid, which has a very endothermic enthalpy of formation (AHf = 534.7 kJ/mol 2.48 kJ/g), explaining the explosive property. 

The electrolysis of antimony trihalides forms an antimide, which is considered as explosive (an analysis shows that it contains halogen). But it is not known if it is the same as the one cited in the tables of enthalpy of formation, unless the explosive antimony mentioned in the tables is formed by a method which is similar to explosive arsenic. The documentation is confusing on this point. 

Its positive enthalpy of formation makes it likely to be highly unstable thermodynamically. Indeed, its explosive decomposition caused numerous accidents. So, 5 g of this compound touched with a metal spatula causes ite detonation. Its crystallisation can also cause its detonation and there should be... 

The CgHs-N Cl- (benzenediazonium chloride) enthalpy of decomposition was calculated. Comparing its value (AH j = -1.5 kJ/g) with the CHETAH criterion C, makes it moderately stable. Accidents have been observed during reactions that are schematised below and these illustrate what has been stated. They are all due to the explosive character of the diazonium sulphides formed. Here is one example ... 

It melts without decomposition although the enthalpy of conversion to silver chloride and oxygen appears to be about —0.5 kJ/g. An explosion while grinding the salt (which had not been in contact with organic materials) has been reported [1]. A powerful oxidant. 

Tests performed on the reactants A and B show an exothermic behaviour and gas formation at temperatures that are in excess of 300°C. The exotherms are in the order of 300 J/g so that explosive properties or a propensity for deflagrations are not anticipated. Testing of reactant mixture samples at different conversion stages of conversion show no need to lower TeXo and confirm the reaction enthalpy of the desired process. 

Numerous aromatic nitro compounds have explosive properties, and thus it is important to understand the role that enthalpy of formation has on the sensitivity and long-term stability of these compounds. We will examine three nitro-substituted aromatic families for which thermochemical data can be found in the literature2,84 derivatives of nitrobenzene, aniline and toluene. The choice of these three families allows us to compare the various electronic effects exerted by the parent functional group. The parent compounds differ electronically with respect to the aromatic ring in that ... 

The enthalpies of formation for nitrated toluenes are listed in Table 7 and then-calculated destabilization energies are given in Table 8. One polynitrotoluene, 2,4,6-trinitrotoluene, is the well-known explosive TNT (61). 

K. -Y. Lee and M. M. Stinecipher, Propellants, Explosives, and Pyrotechnics, 14, 241 (1989). Handrick (Reference 2b) spoke of a salt link or correction of ca 67 kJ mol 1 associated with the formation of a salt from the reaction of an acid and base. From the enthalpy of formation of ethylenediamine from Pedley and of the ethylenediammonium salt of 3-nitro-l,2,4-triazol-5-one from the current reference, and the suggested salt link (x2), the enthalpy of formation of 3-nitro-l,2,4-triazol-5-one is predicted to be —135 kJ mol-1. This is in wonderful agreement with that reported in Reference 103. 

In section 5.2, you used a coffee-cup calorimeter to determine the quantity of heat that was released or absorbed in a chemical reaction. Coffee-cup calorimeters are generally used only for dilute aqueous solutions. There are many non-aqueous chemical reactions, however. There are also many reactions that release so much energy they are not safe to perform using a coffee-cup calorimeter. Imagine trying to determine the enthalpy of reaction for the detonation of nitroglycerin, an unstable and powerfully explosive compound. Furthermore, there are reactions that occur too slowly for the calorimetric method to be practical. (You will learn more about rates of reactions in the next chapter.)... 

Thermodynamic properties for explosion calculations are presented for major organic chemical compounds. The thermodynamic properties include enthalpy of formation, Gibbs free energy of formation, internal energy of formation and Helmholtz free energy of formation. The major chemicals include hydrocarbon, oxygen, nitrogen, sulfur, fluorine, chlorine, bromine, iodine and other compound types. 

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