KNO3 the Chemistry Behind the Boom

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It comes as no big surprise that action films and explosions go hand-in-hand. As most of us have likely experienced, utter obliteration on the silver screen conveys a sense of immediate gratification that other movie-made special effects have trouble measuring up to. In this post, we embrace our inner ten- year old selves and delve into the hugely esoteric field of things going boom. It’s always nice to see the crux of a fast- paced film relate to something other than gunshots and arbitrary detonations, and 21 Jump Street puts forth a noteworthy effort to align a little sense in their big finish. We’d tell you ourselves, but Channing Tatum really said it best in this excerpt from the movie:

“Potassium Nitrate-

Don’t hate.

It’s great.

It can act as an oxidizer.

I didn’t know that,

but now I’m wiser.

It has a crystalline structure.

If you can’t respect that,

you’re a butt-muncher.

It’s a key ingredient in gunpowder.

K-No-Three!”

Tatum plays Jenko, a jock- turned- police officer who goes undercover when assigned to infiltrate a high school in his special police unit. Jenko’s course is switched with that of Schmidt, his brainy partner in crime (or justice), and subsequently is forced to suffer through an AP Chemistry course. His progressive appreciation for the subject pays off, however, when Jenko is able to utilize the knowledge he gained to blow up the limo of a drug dealer in the final chase scene with the creation of an impromptu battery bomb composed of a tequila, potassium nitrate (from shotgun shells) and lithium (from lithium batteries of a camera). Would this concoction have produced the earth-shaking explosion it did?

Lithium batteries and tequila would have produced the exothermic single displacement reaction  Li (s) + H2O (l) → LiOH (aq) +H2 (g). When lithium comes into contact with water a violent reaction occurs, resulting in the release of hydrogen gas inside the tequila bottle, since lithium is higher up in the reactivity series than hydrogen gas due to lithium’s single valence electron in its 2s1 orbital. Furthermore, alcohol is highly flammable and will combust with the hydrogen gas if there is sufficient heat. When Jenko agitated the solution by shaking the bottle, the reaction released the necessary activation energy to combust hydrogen gas and alcohol. Said combustion reaction, 2 H2(g) + O2 (g) → 2 H2O (l), has its oxygen gas provided by the oxidizing agent KNO3.

While the theoretical portion of this analysis has been relatively accurate, the tendency of hollywood to exaggerate now comes into play. Once Jenko placed the lithium inside the bottle, the reaction should have occurred almost instantly with the near immediate release of hydrogen gas, exploding before the bottle left his hands.  Instead, there is a considerable amount of lapse before Jenko throws the battery bomb. As with any reaction, the rate at which the reaction occurs depends on the required amount of activation energy. In this case, the activation energy required to produce the combustion reaction should have been generated from the exothermic reaction between lithium and water. This combined with the shaking of the bottle ultimately would result in the explosion occurring right away. Thus, although the explosion was reasonably designed, its timing was not necessarily as realistic. Moreover, the size of the explosion in the scene is inordinately exaggerated; the use of lithium would not have produced destruction anywhere near that degree. Rather, it would have been more suitable to have used an alkali metal with a more reactive potential in place of lithium to produce an explosion closer to the magnitude of the one shown on the movie screen.

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All in all, screenwriter Michael Bacall’s incorporation of chemistry into an action flick wins high points for creativity, but falls under the standard on the scale of realism. Even Bacall himself acknowledges that in hindsight, he should have “talked to an actual chemist” instead of relying on his fading knowledge back from his own AP chemistry class back in high school. Still, his enthusiasm to portray chemistry as the climatic solution to the problem in the movie is applaudable and exciting.

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Chemistry of War: Stun Guns and Tasers

Continuing the topic of items used to incapacitate the enemy without killing them is with electricity rather than chemically. However, the proper functioning of a Taser is a direct result of the chemical properties of its materialistic components.  The word Taser and stun gun are used interchangeably. However, there are different types of stun guns or Tasers.  Some Tasers utilize properties of projectiles and therefore are more suited when an attacker is out of a victim’s arm reach. Taser is more often used for these types since it is actually an acronym for “Tomas A. Swift’s Electric Rifle”.

A typical Taser requires a 9 volt battery but the Tase Chemistry of War: Stun Guns and Tasers

The proper functioning of a Taser is a direct result of the chemical properties of its materialistic components.  The word Taser and stun gun are often used interchangeably.  However, there are different types of stun guns or Tasers.  Some Tasers utilize properties of projectiles and therefore are more suited when an attacker is out of a victim’s arm reach. Taser is the more commonly used word for these weapons. The word Taser is actually an acronym for “Thomas A. Swift’s Electric Rifle”.

A typical Taser requires a 9 volt battery but the Taser itself is still labeled as several 100kV. The increase in voltage is due to amplifiers and transformers in the Taser’s housing.  A battery is a cell that can convert stored chemical energy into useful energy. The amount of energy is calculated through two types of equations: reduction and oxidation. Reduction consists of an atom gaining electrons and oxidation is an atom losing electrons. Together the transfer of electrons produces a current. Tasers are able to have high voltages through the help of transformers to amplify the low 9 volts but voltages as high as 100kV.  However 100kV is not needed in most cases of authoritative force.

Common lithium battery is made up of -LiCO2(Lithium Cobalt Oxide) and LiC6

The reduction potential equations are:

Li+ +C6 +e– = LiC6      CoO2 + Li+ + e = LiCoO2

A high voltage does not determine how much damage a Taser can do.  Instead, it depends on the amount of current.

Tasers are effective in incapacitating the target by forcing their muscles to contract and release rapidly, causing twitching and convulsions. The human body is controlled by the brain through the use of electrical signals.  An electrical impulse can cause a muscle or group of muscles to contract or expand as necessary.  A Taser injects a foreign electrical impulse into the body and this debilitates a person temporarily (for as long as the Taser is being implemented). The act of a Taser’s current entering a human body is a result of the electron flow.  A Taser includes two parallel electrodes and two smaller test electrodes as shown in the diagram below.  When someone thinks about a Taser, the small test electrodes are probably what their minds first refer to.

As seen in the diagram, the battery offers a current that is amplified by the transformers found in the amplifier circuit.  Near the end of the Taser there are two parallel electrodes, a positively charged electrode and a negatively charged one.  These electrodes are made from a conductive metal plate.  Since these electrodes are placed along the curcuit, there is a high voltage difference between them.  Electrons want to flow between these electrodes, but they are placed too far apart, there is a gap in the circuit.  In comparison, the test electrodes are much closer together.  These smaller electrodes are used by the Taser wielder to see if the Taser is functioning.  If current is flowing through the Taser, then a small bluish, spark will jump between the test electrodes. The crackling spark is composed of air atoms that have been ionized by the electrical energy derived from the battery.  This noisy bright, crackling spark is an image that is normally associated with Tasers.  The parallel electrodes are two far apart to create a such a spark.  A Taser can inflict temporary damage on a person if their body is used to complete the circuit, or to fill the circuit gap between the two main electrodes.  Due to the potential difference in these electrodes, if a conductive object is placed between them, a large current flows.

 Additionally, there are flying Tasers that also use electrodes and a 9 volt batteries.  The main difference in the flying Taser is shown by the diagram below.  The electrodes fly out of the Taser as a projectile.  The electrodes are launched when the trigger is pulled.  The trigger opens a compressed gas cartridge and the electrodes are launched towards an attacker.

 The main risk in using a taser is found when it is used on someone who has heart complications.   Like any other muscle in the body, the heart contracts and expands due to electrical impulses, and a taser interferes with those interactions.  If someone has a weak heart, it is possible for them to die after being tased.  Tasers are weapons and, especially when used near water, can be lethal.  In 2010 a man in Hempstead died after being tased while wearing rain drenched clothing.

Due to the risk of Tasers, authoritative figures are required to use Tasers responsibly.  Here is an article describing how the some departments of the military are beginning to increase their use of Tasers. There is also a branch of authority called the Military Police.  Members of the Military police enforce the laws and regulations of the military.  In order to enforce such regulations members of the Military Police use nonlethal weaponry such as Tasers.  However, in order to encourage humane usage, military police officers are required to be hit with a Taser so they understand

Figure 5:  A picture of a military police officer being hit with a flying Taser gun.  This must be endured in order to earn the authority

r itself is still labeled as several 100kV. A battery is a cell that can convert stored chemical energy into useful energy. The amount of energy is calculated through two types of equations: reduction and oxidation. Reduction consists of an atom gaining electrons and oxidation is an atom losing electrons. Together the transfer of electrons produce a current. Tasers are able to have high voltages through the help of transformers to amplify the low 9 volts but voltages as high as 100kV are not needed in most cases.

Common lithium battery is made up of -LiCO2(Lithium Cobalt Oxide) and LiC6

The reduction potential equations are:

Li+ +C6 +e– = LiC6      CoO2 + Li+ + e = LiCoO2

Tasers function through two launching two prongs into the target. The farther apart the two prongs are, the more voltage is needed to complete the circuit. However a high voltage does not determine how much damage it does, instead it depends on the amount of current. Contact stun guns do not need a large voltage since the distance between the charge electrodes is fixed.

Tasers are effective in incapacitating the target by forcing their muscles to contract and release rapidly, causing twitching and convulsions. The human body is controlled by the brain through the use of electrical signals.  An electrical impulse can cause a muscle or group of muscles to contract or expand as necessary.  A Taser injects a foreign electrical impulses into the body and this debilitates a person temporarily (for as long as the Taser is being implemented). The act of a Taser’s current entering a human body is a result of the electron flow.  A Taser includes two electrodes and two smaller test electrodes as shown in the diagram below.  When someone thinks about a Taser, the small test electrodes are probably what their minds first refer to.

As seen in the diagram, the battery offers a current that is amplified by the transformers found in the amplifier circuit.  Near the end of the Taser there are two parallel electrodes a positively charged electrode and a negatively charged one.  These electrodes are made from a conductive metal plate.  Since these electrodes are placed along the surface, there is a high voltage difference between them.  Electrons want to flow between these electrodes, but they are placed too far apart, there is a gap in the circuit.  In comparison, the test electrodes are much closer together.  These smaller electrodes are used by the Taser wielder to see if the Taser is functioning.  If current is flowing through the Taser, then a small bluish, spark will jump between the test electrodes. The crackling spark is composed of air atoms that have been ionized by the electrical energy derived from the battery.  This crackling spark is an image that is normally associated with Tasers.  The parallel electrodes are two far apart to create a spark.  A Taser can inflict temporary damage on a person if their body is used to fill the circuit gap between the two main electrodes.  Due to the potential difference in these electrodes if a conductive object is placed between them, a large current flows.

Additionally, there are flying Tasers that also use electrodes and a 9 volt battery.  The main difference in the flying Taser is sown by the diagram below.  The electrodes fly out of the Taser as a projectile.  The electrodes are launched when the trigger is pulled.  The trigger opens a compressed gas cartridge and the electrodes are launched towards an attacker.

The main risk in using a stun gun is if the target already had heart problems and the shock is applied near the chest which can lead to cardiac arrest and/or death.

Here is an article of the military more recently starting to use stun guns. There is also a branch of authority called the Military Police.  Members of the Military police enforce the laws and regulations of the military.  In order to enforce such regulations members of the Military Police use nonlethal weaponry such as Tasers.  However, in order to encourage humane usage, military police officers are required to be hit with a Taser so they understand.

Conclusion: Tear Gas, Pepper Spray, and Chemical Weapons (Oh My!) 

According to reputable official the Honorable Mr. Andrew C. Weber, the Assistant Secretary of Nuclear, Chemical, and Biological Defense programs, “the Office of the Assistant Secretary of Defense for Nuclear, Chemical and Biological Defense Programs has a wide range of duties related to countering Weapons of Mass Destruction (WMD) threats.  Their team of top scientists helps us understand these threats and engage in activities and programs to counter them.  Their duties include overseeing Department of Defense science and technology investments in countermeasures that will enable the United States forces to prevent, protect against, and respond to WMD threats”. However there is still one chemical weapon that is marketed to the masses today and even used against protests: tear Gas.

 

Tear gas was first introduced World War I by the French. It was not very concentrated, and the Germans hardly noticed it was being used. In August 1914, the French fired 26 mm grenades containing ethyl bromoacetate, but the low concentration, only approximately 19cm³ per grenade, was not enough to bother the Germans. Afterwards, due to shortages of bromine, the primary chemical was switched to chloroacetone. The Germans then retaliated with a tear gas of their own making, using it for the first time in October of 1914 on the British. Again, the weapon was so dilute that the enemy combatants did not even notice.

Peaceful protesters in Tahrir Square attempt to flee from the noxious tear gas

 Since its debut in the Great War, tear gas, and its famous derivative pepper spray, has transformed from an ineffective weapon of war to a highly efficient tool for dispersing protesters. It has become a lynchpin in the arsenal of modern authoritarian regimes and has seen widespread use in recent years, with the Arab Spring and the Turkish protests being the more high-profile international cases. In an especially ironic incident, tear gas manufactured in the US, the great champion of democracy, was used on protesters in Tahrir Square attempting to enact some democratic reform. In Turkey, when Prime Minister Erdogan tried to seize historic sites and develop them for his cronies, protesters invaded Taksim Square; they were tear gassed. Luckily for them, the tear gas brought international attention to their plight, but that cannot be said of all tear gas victims.

A doctored photograph which emphasizes the inhumane actions of Lt. Pike, who had pepper sprayed a peaceful protestor.

 

Another event exemplifying the political, rather than physical, power tear gas can have was the UC Davis Occupy protest that involved Lt. Pike, a police officer who had pepper sprayed a peaceful protester for no apparent reason. The ensuing media firestorm brought new attention to the waning Occupy Movement, showing that chemical weapons aren’t always so bad. Also, the image of the cop pepper spraying the protesters birthed many amusing pictures, another positive effect of chemical weapons.

3-D Model of 2-Chlorobenzalmalononitrile (CS)

Although tear gas has numerous different forms, 2-Chlorobenzalmalononitrile (also known as CS) is the most common. CS has a chemical formula of C10H5ClN2, composed of several cyanide functional groups, Due to the hydroscopic nature of aerogels, a type of colloid, when silica aerogel is combined with CS, the fluidity, water resistance, chance of exposure and intensity of the symptoms increase.  CS gas is synthesized by the reaction of 2-chlorobenzaldehyde and malononitrile through Knoevenagel condensation. This reaction is composed of two steps: first, the nucleophilic addition of an active hydrogen compound to a carbonyl group and second, a dehydration reaction in which a molecule of water is removed. of the symptoms increase

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ClC6H4CHO + H2C(CN)2 → ClC6H4CHC(CN)2 + H2O

There are a couple major components in tear gas. Charcoal is used as an ignitor when combined with potassium nitrate allowing the can to combust. This is because potassium nitrate gives off great quantities of oxygen when it burns, feeding the fire, while charcoal will begin to smolder when the pin is pulled. Silicon is also added so that when the exothermic reaction of potassium nitrate occurs causing super hot glass droplet to forms, igniting the other compounds. The sucrose in the can acts as a fuel source for the fire at a relatively low temperature, vaporizing the O-Chlorobenzalmalononitrile, a lachrymator, irritating the eyes or the nose. Potassium chlorate is an oxidizer creating some of the smoke, while magnesium carbonate is used to to keep the solution slightly neutral. This is all dispersed in nitrocellulose, a sticky binding, to create a homogenous mixture.

Although technically banned under the UN Convention on Chemical weapons, tear gas is not nearly as lethal as other compounds such as Ricin or Sarin gas. In fact it has to be 25 grams per cubic meter for it be lethal when only concentrations 4 grams per cubic meter are used to disperse crowds. However it is still worrying to note that chemical weapons are not just abstract concepts, created in sinister labs in shady countries, but actually used today, even here in the US.