Oxygen balance calculations

If the DTA or DSC are used as true screening tools in experimental safety testing, which in other words, means that there is not much more information available on the substance to be tested than the explosibility assessment according to the oxygen balance calculation, it may generally be recommended to use stainless-steel sample containers, which can withstand pressure up to 200 bar for the first tests. 

Larger particles of charcoal in a pyrotechnic mixture will produce attractive orange sparks in the flame, a property that is often used to advantage by the fireworks industry. In this case, they are considered to be an added component that does not participate in the primary pyrotechnic reaction, and are not included in oxygen balance calculations. 

Figure 9.11 Sample oxygen balance calculations for explosives. 

A Figure 9.12 Oxygen balance calculations when a mix of explosives is used. 

An oxygen balance can be used to calculate water formed by the cniubus-tion ol coke ... 

The heat of decomposition and/or reaction (in absence of ambient oxygen) is calculated (see Section 2.2.3.2). If the value of the oxygen balance is less than -240 or higher than +160 (Table 2.12) and the calculated heat of reaction/decomposition is less than 100 cal/g (420 J/g), the substance in its pure form is regarded as having a very low potential to produce a deflagration or detonation [10,11]. 

Accurate determination of Tv often involves a series of tedious calculations of the equilibrium composition of the explosion products at several temperatures. Von Stein Alster of PicArsn presented a new method which offers a simple general treatment for arriving at equilibrium compositions for C-H-N-0 explosives of any oxygen balance. The novel feature of this method which is described in PATR 2501 (Ref 40a) is that the temperature of explosion can be determined directly from the known heat of... 

Explosive Power vs Oxygen Balance, Correlation of. The relationship of oxygen balance to expl power as measured by ballistic mottathas been studied empirically. Starting from modified oxygen, balance developed for detonation velocity calculations, a numerical measure called the power index is derived which correlates closely the features of molecular structure with.the power values. Expl power has also been expressed as an additive function of details of molecular structure. This is the basis for a method whereby power values may be derived which agree with experimental results to about... 

Q Construct a fully balanced equation lor the oxidation of Cm by molecular oxygen, and calculate the standard potential for the... 

Calculation of the oxygen balance is carried out by taking into consideration the quantity of oxygen supplied by the oxygen carrier and that required by the combustible ingredients of the explosive mixture. The figures for the most frequently used ingredients are tabulated below. 

An alternative method for calculating the oxygen balance is shown in Equation 5.2. Here, the oxygen balance Q is calculated from an explosive containing the general formula with molecular mass M. 

The balanced reaction formulae and calculated oxygen balances for some explosive substances are presented in Tables 5.1 and 5.2, respectively. 

The oxygen balance does not provide information on the energy changes which take place during an explosion. This information can be obtained by calculating the heat liberated during decomposition of... 

Most explosive and propellant compositions contain a mixture of components so as to optimize their performance. Some of the components may not contribute to the heat liberated and may not even contain oxygen. These materials may however, contribute to the gaseous products and reduce the actual temperatures obtained on detonation of the explosive or burning of the propellant. An example of a typical mixed explosive composition is one which contains 60% RDX and 40% TNT, and where the heat of explosion Q has been optimized. In order to calculate the values of Q and V for this composition the oxygen balance and the reaction for decomposition need to be determined. But even before these can be calculated the atomic composition of the mixture must first be established. 

Note In Vol l,p A515 of this Encyclopedia is described a method for calcn of oxygen balance for individual compds, but nothing is said about calcn of OB s for mixtures. The simplest method is to proceed as follows a)Calculate OB s of individual components and divide the values by 100 b)Multiply each OB by the corresponding percentage in the m ixture and then add the resulting values... 

Shaw calculated the isokinetic point between homolysis and elimination as 770K for mononitro- and vicinal dinitro-alkanes and as 370K for gem-dinitro species [51]. In gem-polynitro species the C-N02 bond is weaker than in mononitro compounds due to inductive effects [52] thus, homolysis is thought to be the principal decomposition pathway in 2,2 dinitropropane and hexanitroethane [48]. Octanitrocubane has recently been synthesized (Fig. 6). Its crystal density was lower (1.979 g/cm3) than the predicted 2.1 [53]. Like hexanitrobenzene, octanitrocubane has a perfect oxygen balance, but at this point it appears unlikely that further development of this compound will be undertaken. 

Write a balanced chemical equation for the formation of vanadium(V) oxide. Use the known mole ratio of vanadium to oxygen to calculate the unknown amount of oxygen. 

In the case of industrial explosives containing an excess of oxygen (-> Oxygen Balance), it is conventionally assumed for the calculated values that only C02, but no CO, and also that only H20, N2 and excess 02 are contained in the fumes. In reality the reaction is much more complex, and the product may in fact include CO, NO, N02, CH4 and many other substances, if the explosive contained sulfur and/or chlorine compounds. 

The most favorable composition for an explosive can be easily calculated from the oxygen values of its components. Commercial explosives must have an oxygen balance close to zero in order to minimize the amount of toxic gases, particularly carbon monoxide, and nitrous gases, which are evolved in the fumes. 

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