Explosives commonly require some stimulus, like a blow or a spark, to provoke them to liberate their energy, that is, to undergo the change which produces the explosion, but the stimulus which sets off1 the explosive does not contribute to the energy of the explosion. Chapter i properties of explosives an explosive is a. Many substances not ordinarily classed as explosives may do one, or even two, of these things. Azidoazide azide c2n14 is a novel chemical, since it was made in 2010 by the american military and german scientists. The composition of explosives is balanced chemically to produce the desired effects in blasting.
This is the explosive of choice for purposes such as the quarrying of large blocks of stone for building, and for use as a propellant in guns. Thus the number of atoms of an element in the reaction s products is equal to the number of atoms of that element in the original reactants. A pyrotechnic article is an article containing one or more pyrotechnic substances. A high explosive detonates, meaning the chemical reaction moves through the explosive at a speed greater than the speed of sound. For many warheads that energy is stored in the form of chemical explosives. Normally, the forensic examination of the preand postblast physical evidence lacks speci. A high explosives detonation provides both shock, which fractures or breaks the rock, and. These reactions produce gas n 2 to fill the airbag and convert nan 3, a highly toxic substance, to. High explosives detonate, whereas low explosives deflagrate or burn. Such materials are often mixtures of separate oxidizer and fuel compounds. Chemistry is an interesting science, which is simply vital in our lives. Chapter i properties of explosives an explosive is a material.
An explosive or explosive material is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. The top 10 most dangerous chemical reactions mel chemistry. An explosive substance is one which reacts chemically to produce heat and gas with rapid expansion of matter. The reaction of monomers forming polymers is exothermic. It was used widely in world war ii and remains common in military applications rdx is often used in mixtures with other explosives and plasticizers or. A chemical reaction of a solid substance can occur only on its surface fig.
Synthesis of ammonia leads to the production of fertilizer ammonium nitrate and to the production of. Typically the chemical reaction is 90% complete in 106 to 109 second. Full scale chemical neutralization of bulk explosives chemical neutralization of bulk explosives abandoned on demilitarization equipment onsite demilitarization of recovered underwater munitions insitu remediation of explosives contaminated soils summary and conclusions. Hydrogenation reactions are often carried out under pressure with a.
Alow explosive material,suchasgunpowder,smokelesspowderorfireworks,burnsmuch slower. An explosive substance or mixture is a solid or liquid substance or mixture of substances which is in itself capable by chemical reaction of producing gas at. In this exercise we will observe several chemical reactions. If the reaction proceeds slowly, the released energy will be. Tnt explodes by a fast monomolecular reaction, and its speed of ignition is several kilometres a. The energy goes into the motion of the explosive products, creating the high pressures and fig. A montage of some pretty explosive and dangerous chemical reactions. Sensitiser provides the heat source hot spot to drive the chemical reaction of oxidiser and fuel. An explosive is a chemical material that is capable of extremely rapid combustion resulting in an explosion or detonation.
Fine particulates of explosives may also be dislodged during the bomb making process and adhere to packing material, as well as the clothing and skin of a. The effect of temperature on the rate of a chemical reaction may be demonstrated strikingly by introducing a 12inch length of black match into a 10inch glass or paper tube which. The other class is potentially explosive chemicals pecs, which include peroxidizable organic chemicals. Chemical and physical factors that influence no x production during blasting exploratory study. An explosive item is an item containing one or more explosive chemicals. Hazardous reactions of aluminum powder with water in the propellant, explosive and pyrotechnic pep industries. Explosive chemicals can release tremendous amounts of destructive energy rapidly. The coefficients we often place in front of one or more of the formulas in a chemical equation reflect this fact. Because flammability, toxicity, and pressure buildup may become serious when gases are exposed to heat, gases should be stored only in specifically designed and designated areas. Thermal chemical signatures a b s t r a c t forensic identi. All reaction rates are consistent with known activation parameters and reaction conditions, and there is no indication of unique chemical processes connected with the. An explosive substance is a solid or liquid substance or mixture of substances which is in itself capable by chemical reaction of producing gas at such a. In a small scale reaction, most of the heat is lost to the environment, thereby preventing an explosion.
Like an ordinary combustion wave, a detonation wave derives its energy from the chemical reactions in the material, but the energy transport occurs not by thermal conduction but rather by a highspeed compres. There are two major categories, high explosives and low explosives. Another example is the reaction between hydrogen and oxygen, which is a highly favorable exothermic reaction. Azidoazide azide is the most reactive and explosive compound that is ever made by humans, because in its sequence there are many unstable nitrogen atoms, so that when nitrogen atoms want to form a stable state, they will release a large amount of energy and causing an explosion. The explosive reaction is initiated by the shock wave see blast, and the reaction seppliee enurgy to maintain the shock.
However, as many textbooks tell us, if you want to conduct chemical experiments, you need to know the safety rules, as some experiments are dangerous both to people and to the environment. Chemical reactions, proposes amendments of the manual of hazardous chemical reactions, nfpa no. Chemical explosives for a substance to be a chemical explosive, it must undergo a chemical reaction that releases a lot of energy, making the temperature and gas pressure rise rapidly. Properties of explosives definition an explosive is a material, cither a pure single substance or a mixture of substances, which is capable of producing an ex. In the absence of decomposition catalysts, it has 951. High explosives are further divided into initiating, or.
The term applies to materials that either detonate or deflagrate. It is a rapid chemical reaction, initiated by the heat accompanying a shock compression, which liberates sufficient. The only explosive used for propulsion and blasting from until 1850 a history of greek fire and gunpowder j. If more than one hazardous reaction is carried out, the reactions should be. It is a white solid without smell or taste, widely used as an explosive. The energy is typically mechanical in nature and takes the form of a shock wave or the kinetic energy of fragments. By contrast, a high explosive like trinitrotoluene tnt, has oxygen as part of the single, explosive molecule. Because of the stabilizer elements, it takes a considerable shock to set off this reaction. A high explosive is any chemical mixture that detonates with a reaction velocity over 5000 feet per second. Refer to the safety data sheet sds for more information. Feb 04, 2011 heat, impact, friction, detonation, or other suitable initiation, undergoes rapid chemical change. Fact sheet on globally harmonized system for classification.
Most chemicals that are used in research and teaching laboratories are stable and non explosive at the time of purchase. Reactions of organic compounds in explosivedriven shock. A high explosive detonates, meaning the chemical reaction. When planning a reaction, consider the potential for explosion and plan accordingly. The use of the word explosive can have different meanings and interpretations. Several solvents commonly used in the laboratory can form explosive reaction products through a relatively slow oxidation process in the presence of atmospheric oxygen. Stein a release of mechanical, chemical, or nuclear energy in a sudden and often violent manner with the generation of high temperature and usually with the. A device placed or fabricated in an improvised manner incorporating destructive, lethal, noxious, pyrotechnic, or incendiary. He produce a defining supersonic overpressurization shock wave. Since an adequate supply of oxygen cannot be drawn from the air, a source of oxygen must be incorporated into the explosive mixture. Current trends in explosive detection techniques j. Based on your observations, you will classify each of the reactions and write chemical equations for these reactions. Just as with other explosives, you need to apply some energy to c4 to kick off the chemical reaction. There are 3 kinds of explosions which are unconfined explosions, confined explosions and explosions caused by explosives attached to the.
Nitroglycerin is a chemical explosive that was discovered by italian chemist ascanio sobrero in 1846. Flammability, liquid anhydrous hydrazine is very stable and non explosive. Accordingly, gunpowder explodes at only a few metres a second. A chemical explosive is a compound or mixture which, upon the application of heat or shock, decomposes or rearranges with extreme rapidity, yielding much gas and heat. The risk of explosion can be greatly reduced by following storage and handling practices that are compatible with the properties of these materials 23. Sensitisers are generally small air bubbles or pockets within the explosive. In either case, a large amount of energy must be released. Explosives, in contrast, support very high speed combustion known as detonation. An explosive substance is a solid or liquid substance or mixture of substances which is in itself capable by chemical reaction of producing gas at such a temperature and pressure and at such a speed as to cause damage to the surroundings. The propensity of explosive vapors and explosive particles of low volatility to adsorb strongly to bulk surfaces 26 or dust particles is the basis for several explosive detection schemes. Forensic analysis methodology for thermal and chemical.
Ten amazing and occasionally explosive chemical reactions. Page 1 of 2 explosives university of michiganflint. Detonation occurs when the rate of chemical decomposition is greater than the speed of sound. When the car undergoes a headon collision, a series of three chemical reactions occur inside the gas generator. G of prudent practices in the laboratory national research council for a discussion of some explosive hazards that may be encountered in the laboratory. Pyrotechnic substances are included even when they do not evolve gases. It is a rapid chemical reaction, initiated by the heat accompanying a shock compression, which liberates sufficient energy, before any expansion occurs, to sustain the shock wave. Classification of explosives explosives are categorized as highorder explosives he or loworder explosives le. J kelly basic books 2004 15% 10% 75% 3 megajoules per kilogram 1025% of your yearly phone energy consumption charcoal. Tnt trinitrotoluene is the most widely known example.
High explosives are solid in form and are commonly termed condensed explosives. An introduction to chemical reactions, gases, and chemical. This browning of the apples surface is a chemical reaction between the molecules at the surface of the apple and oxygen from the air fig. Never try it without professional guidance and facility.
The detonation wave spreads from the point of initiation as a nearly spherical wave, almost like a. The various stimuli to which explosives respond and the mannci. A material in which the first three factors exist cannot be accepted as an explosive unless the reaction can be made to occur when needed. Rdx is an organic compound with the formula o 2 n 2 ch 2 3. An explosive article is an article containing one or more explosive substances. Examples of he include tnt, c4, semtex, nitroglycerin, dynamite, and ammonium nitrate fuel oil anfo. However, the reaction wont start spontaneously by itself unless ignited by a spark explosive.
A pyrotechnic chemical is a chemical designed to produce an effect by heat, light, sound, gas or smoke or a combination of these as the result of nondetonative selfsustaining exothermic chemical reactions. Chemically, it is classified as a nitramide alongside hmx, which is a more energetic explosive than tnt. It was the first explosive developed that was more powerful than black powder, nitroglycerin is a mix of nitric acid, sulphuric acid, and glycerol, and it is highly volatile. Detonation supersonic chemical reaction, shock wave. In chemical reactions, atoms are neither created nor destroyed. Heat, light, mechanical shock, and certain catalysts initiate explosive reactions. Indeed, mixture of hydrogen and oxygen remains stable at room temperature. Guidelines for explosive and potentially explosive. Chemical reactions used to generate the gas inside the airbag is a gas generator containing a mixture of nan 3, kno 3, and sio 2. The lower the hydrazine concentration, the milder the reaction. Chemical and physical factors that influence n0x production. A reaction must be capable of being initiated by the application of shock, heat, or a catalyst in the case of some explosive chemical reactions to a small portion of the mass of the explosive material. Higson direct detection of explosives on solid surfaces by mass spectrometry with an ambient ion source based on dielectric barrier discharge na na, chao zhang, mengxia zhao, sichun zhang, chengdui yang, xiang fang, xinrong zhang. Amatol is a chemical that is classified as a powerful explosive high explosive that has.
There are many chemical reactions that will release energy. Explosive admixture with drill cuttings, loss of fuel oil in ammonium nitrate and fuel oil anfo from wicking, ammonium nitrate dissolution with water, degree of explosive confinement, anfo density, and critical diameter were identified as contributing factors to. Despite much research into the mechanisms by which shock waves initiate chemical reactions in explosive materials, the reaction processes that take place in. Part iii has been submitted for ballot to the sectional committee on hazardous chemical reactions, which consists of 70 voting members, of whom 10 have voted affirmatively. Chemical neutralization and destruction of bulk and. Explosive reactions there are many chemical reactions that will release energy. Encyclopedia of explosives a compilation of principal.
Miller1 and ana navarro2 although aluminum powder has been successfully used in propellant, explosive and pyrotechnic pep for generations, there are hazards associated with allowing the material to become wet. For example, when a cut apple is left exposed to air, it soon begins to turn brown. Cached or stockpiled munitions within the current theater of operations may provide the explosive materials to would be enemy bombers. The names and chemical formulas of the substances used in this exercise are summarized in table 1. Large volumes of highly heated gases are evolved that exert pressure on the surrounding medium.
447 512 61 1385 582 1028 1494 617 1009 796 215 1428 1126 1519 1385 143 1158 419 1387 787 69