Chemistry Report on Explosives

Chemistry Report on Explosives Chemistry Report on Explosives What is meant byoxidation and show how oxidation reactions are used to cause explosions. Oxidation is the term used for the combinationof a substance with oxygen, or in general any reaction where an atom ormolecule loses electrons. This can be shown as: C (s) + O2 (g) CO (g) S=solid, g=gas Gunpowderor black powder is the oldest explosive we know. It is made up of a mixture ofpotassium nitrate (also known as saltpetre or KNO 3 ), charcoal, andsulfur in different proportions. When gunpowder is manufactured today, it ismade with the ratios 7.5:1.5:1 by mass (2). Bothgunpowder and dynamite have within them substances which are readily availableto oxidation. The oxygen which is used for the oxidation is an intrinsic partof the mixture, and is held within them in the same manner that oxygen isstored in the chemical potassium chlorate. Whengunpowder is ignited, this oxidation is extremely rapid, and a large volume ofgas is produced. The gasses are under ex treme pressure, which causesthem to expand rapidly. Heat is produced causing the gas particles toaccelerate, creating even more pressure. If the gas expands faster than thespeed of sound, this creates a shockwave. The pressure produced by the gassesis what causes parts of the bomb (shrapnel) to be propelled far and wide atvery high speeds(1). Thespeed at which something oxidises is dependant on its potential to interactwith oxygen. The greater number of unstable electrons that a molecule or atomhas to lose, the quicker it will be oxidised (3). b)  Ã‚  Ã‚  Ã‚  Ã‚  Give an account of thedevelopment of chemical compounds for use in explosives. Describe theadvantages of each new chemical explosive over its predecessors, and describehow the explosives were adapted to make them safer and more effective. (9marks) It is thought that the firstexplosive discovered was ‘black powder’, originating in 10th Century China. Itwas used for ceremonial fireworks. In Europe, 1242 saw the formula for blackpowder being published by Roger Bacon. The refinement of the substance closelyfollowed after the gun was invented by Berthold Schwartz in 1300. Around thistime, black powder was being used for removal of rocks, the teqnique was knownas fire setting, but this was replaced with blasting at the beginning of the17th Century. There are records of blasting in America from 1773 (4). The production of black powderwas rapidly increased during the American Revolution. By the turn of thecentury, the commercial production of the explosive had grown from 25 millionto 100 million (2). In 1846, Nitroglycerin wasdiscovered by Ascanio Sobrero. Nitroglycerin plasticizes collodion which is aform of nitrocellulose to form blasting gelatin. This is a very powerfulexplosive. The discovery of this action led to the advancement of ballistite, thefirst double-base propellant and a precursor of cordite. Alfred Nobel built a factory toproduce it in 1861 in Sweden. An advantage of nitroglycer in was its massiveexplosive power, but it was very difficult to transport as it is a liquid,which used black powder to ignite it. It could also freeze and had toxic fumeswhich caused severe headaches (5). In 1867, Nobel accidentallyinvented Dynamite and he went on to patent his mixture. It was a greatdiscovery, being more powerful than black powder, with a higher detonationvelocity which made it much more effective breaking rock as it not only moved,but broke apart the rock