Science-is-a-Blast

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By Ariana Lema and Anya Rozman =Introduction=

Dynamite was first created by Alfred Nobel, whose goal was to help miners; and that is its main use today. It is a highly explosive and //dangerous// material. The chemical reaction that takes place as it explodes is 4C3H5(NO3)3(l) --> 6N2(g) + 12CO2(g) +10H2O(g) + O2(g) Its main component is nitroglycerin, the cause of the explosion, and it is detonated by blasting caps.

= = = = = = = = = = = = =History=

The roots of the dynamite date back to 1846 when Nitroglycerin, an explosive liquid, was invented by Ascanio Sobrero by treating glycerol with a mixture of nitric and sulphuric acid. This exothermic reaction is very dangerous and was widely banned. It was colorless in its liquid form and extremely unpredictable as to when the explosion would occur. In 1867, dynamite was invented by Alfred Nobel; a Swedish chemist, engineer, innovator, and inventor. It received U.S. patent no. 78,317. Nobel took the invention of nitroglycerin and turned it into an explosive that could be used for mining. It was a much safer concept and much more useful. 5 = = Alfred Nobel took the original concept of an explosive liquid, Nitroglycerin, and turned it into something more convenient to handle and much safer. At first he considered naming it "Nobel Safety Powder" but instead settled upon 'dynamite', named after the Greek word for 'power' ( Schück & Sohlman)

Blasting caps are small devices that initiate the detonation of dynamite, a much larger, powerful secondary explosive- such as dynamite. They've come a long way. The first blasting cap (detonator) was used in 1745 by Dr. Watson of the Royal Society.Benjamin Franklin produced the first commercial cap in 1750 in Philadelphia. It was a paper tube full of black powder with two wires leading to both sides close to each other, but not touching.In 1822 Dr. Robert Hare produced a hot wire detonator. This blasting cap ignited a pyrotechnic mixturee and theen a charge of tamped black powder.In 1864, Alfred Nobel created the first Pyrotechnic Fuse blasting cap to detonate dynamite using mercury fulminate.In 1868, a cap that combined mercury fulminate and a spark gap ignitor was introduced by H. Julius Smith- the first electric blasting cap to detonate dynamite.In 1875, Perry Gardinr and Smith developed modern blasting caps which combined the hot wire detonator with mercury fulminate explosive.Electric match blasting caps were developed in the early 20th century in Germany and reached the U.S. by the 50s when ICI International bought out Atlas Powder Co. The same cap is used today. (Cooper) =Chemistry=

= = In dynamite, the explosive is still nitroglycerin since no chemical reaction between it and the kieselguhr takes place. The reaction for combustion is as follows:

4C3H5(NO3)3(l) --> 6N2(g) + 12CO2(g) +10H2O(g) + O2(g) 3

The process of nitroglycerin exploding is categorized as a combustion reaction. This is because the fuel (the nitroglycerin itself) is made of hydrogen and carbon. In the presence of oxygen, the hydrogen will react to form water vapor, and the carbon will react to form CO2. Both of these reactions with oxygen will release heat, meaning the reaction will be exothermic. 1

Of the thousands and thousands of exothermic reactions, why do only certain ones react explosively? The reason has to do with the speed at which they react. If two compounds were react slowly, the energy they produce will be distributed into the surroundings and lost. However, if the reaction is instantaneous, the energy will be unable to escape fast enough before more is released, thus trapping a large quantity in a small volume and quickly heating the gases directly around it. Those gases will rapidly expand with enough force to carry debris particles with them. 2

That just leaves the question of why it reacts quickly instead of burning. When most things burn, they require an activation energy so their molecules can react with the oxygen in the air. Nitroglycerin has three nitrate groups, which by definition contain three oxygens eat. This means that Nitroglycerin has an internal oxidant. 6 Therefore, while things which burn need the energy to break apart their bonds and then bond to oxygen, nitroglycerin needs only to break its bonds and has instant oxygen, and in fact mole for mole, an abundance of it. That is what makes it so unstable; it only needs a little to set off a chain reaction. Simply jostling a container of it would be enough.

So just how powerful is this stuff when it explodes? Using the heats of formation for the products and reactants, we can calculate the kilojoules of energy given off by the decomposition above. The heats of formation are in the table below: 4
 * = **Molecule** ||= **Heat of Formation** ||
 * = Nitroglycerin ||= -364 kJ/mol ||
 * = Carbon dioxide gas ||= -393.5 kJ/mol ||
 * = Water vapor ||= -241.8 kJ/mol ||

Derived from Hess's Law, this equation states that the sum of the heats of formation for the products minus the sum of the heats of formatio for the reactants, will find us the total number of kJ given off. Now all that is left to do is plug in.

[(6 moles N2 x 0)+(12 moles CO2 x -393.5 kJ/mol)+(10 moles H2O x -241.8 kJ/mol)+(1 mole O2 x 0)] - [4 moles 4C3H5(NO3)3 x -364 kJ/mol] = [0+(-4722)+(-2418)+0]kJ - 1456kJ = -7140kJ - (-1456 kJ) = -5684 kJ

That means that 5684kJ of energy are released from just four moles of nitroglycerin exploding. That's 6.25kJ per gram.

How can a reaction like that be stabilized just by being mixed with something like dirt? Science doesn't know yet. If there were a definitive answer, we would be able to predict the compound which would best work in stabilizing nitroglycerin. However, all we have now is trial and error, so therefore, the secret is yet to be known. Furthermore, due to dynamite's potential as a tool for terrorism, much that is known about it is not open to the public domain. [Document 7].

=Importance=

= = The stabilization of dynamite had a huge impact on history. Suddenly, man had tamed a massively powerful explosion, and the applications were endless. Nobel himself considered it the weapon to end all wars, although it had significant use in World War I. For the most part though, it was used for what it was invented for: mining. The shape that the paste-like nitroglycerin was molded into was fitted into holes in the mountain and set off to clear large portions of rock at a time. Later, a similar method was used to blast holes through mountainsides to build railroads, but that was not the only type of construction project that boomed because of dynamite. Reservoir such as the Panama Canal could not have been accomplished without an effective and controllable explosive.

However, the government didn't always benefit. While dynamite built up nations, it also destroyed some. The 19th century was one of the great clash between the middle and working classes all across Europe. While the former was able to afford guns, the latter had to rely on what the government provided them with, and that was dynamite or the ingredients thereof. It was used by the Russians in the October Revolution, and by the Fenians against the British, as well as many more. Easy to make, nitroglycerin and therefore dynamite was the explosive that changed the course of history a dozen times over. 8

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 * 1) Kumar, Sunil. "Combustion Basics." // Energy Solutions Center // . Sept. 2002. Web. 01 June 2010. < [] >.
 * 2) "Chemical Explosives." // Federation of American Scientists // . 20 Jan. 1998. Web. 31 May 2010. < [] >.
 * 3) Earhart, Alan D. "CHEM 1090-General Chemistry I Lecture Notes." 01 Nov. 2008. Web. 1 June 2010. .
 * 4) "Calculating Changes in Enthalpy (ΔH)." Northern Arizona University. Web. 1 June 2010. 
 * 5) "Nitroglycerine and Dynamite." // Nobelprize.org // . Nobel Web AB, 2010. Web. 02 June 2010. < [] >.
 * 6) Senese, Fred. "General Chemistry Online: FAQ: Redox Reactions: Why Is Nitroglycerin Explosive?" // General Chemistry Online // . 15 Feb. 2010. Web. 02 June 2010. < [] >
 * 7) Rozman, Michael G, PhD. "Nitroglycerin Stabilization." Personal interview. 2 June 2010
 * 8) Kelly, Jack. "Big Bang: The Deadly Business of Inventing the Modern Explosives Industry." // American Heritage // . American Heritage Publishing, Summer 2006. Web. 4 June 2010. < [] >.
 * 9) Schück & Sohlman (1929), p. 101.
 * 10) Cooper, Paul W., //Explosives Engineering//, New York: Wiley-VCH, 1996.