Of an Explosion Characteristics Not like a fire does not need oxygen Energy and gases released as products of rxn Expanding gases produce a pressure wave longitudinal wave X Compressions where coils are close together ID: 772801
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Of an Explosion Characteristics
Not like a fire – does not need oxygen Energy and gases released as products of rxn Expanding gases produce a pressure wave (= longitudinal wave) X
Compressions = where coils are close together Rarefactions = where coils are far apart Wave transfers energy from one end to other Explosion energy forces particles in air to move back and forthIf in container, stretches until bursts sending flying debris ( = shrapnel) all over
Explosives = chemicals that react under certain conditions to cause explosions Most are solids 2 categories – based on rate of reaction 1. low – slower, can burn rather than explode 2. high – faster, violent
Low Explosives Burn rapidly, but explode only when confined Produce combustion rxn = deflagration = rapid, intense burning - produces pressure wave w/ a speed of less than 340 m/s (speed of sound)Used as propellants - produces enough gas and energy to push objects away from original explosion
Need a small amount of energy to ignite low explosive Examples : Black powder used to make safety fuses – carries spark to another explosiveSmokeless gunpowder – safest and most powerful
Fireworks = black powder or smokeless gunpowder and a fuse - rxn produces gases putting pressure on paper surrounding firework -> explosion - elements added to firework give off the colors
Natural gas – when mixes w/ oxygen can explode if ignited - smell added to it to detect it
High Explosives Materials that detonate = results in violent disruption to the surrounding areaDo not need to be confined to explodeMany decompose upon detonationExample – TNT (C7H5N3O6) 2 C7H 5N3O6 3N2 + 5H 2 O + 7CO + 7C (Carbon will leave black soot)
Detonate easily producing pressure wave that moves as fast as 8,500 m/s = shock wave Widespread damageUsed to blast or shatter a target2 categories – primary and secondary
Primary – dangerous - sensitive to heat, pressure, and movement - used to detonate other explosives or in shotgun shellsExamples – lead styphnate, mercury fulminate, nitroglycerin
Secondary – relatively safe - not as sensitive, but can cause very violent explosions - used for military or commercial purposesExamples – TNT and dynamite (= nitroglycerin and silica mixture)
Categories based on usage 1. commercial – mining, road construction, demolition 2. military – ex. RDX (form of C-4), PETN, TNT 3. improvised explosive – illegal; low explosives in a container - used for terrorism & guerrilla warfare