Science Makes Sense: Week 20- Chemistry and Social Justice: agents of war, mustard gas, napalm, white phosphorus.

Anyone who grew up in the ’60s will never forget that horrific, poignant picture of a young Vietnamese girl running naked with her mouth open with fear. The U.S. Forces had just dropped napalm in that village where the girl lived.  That picture galvanized the anti -war movement and could have played a significant role in ending the senseless, Vietnam War.

Napalm was originally manufactured for World War 2 and was used initially as a flame thrower against German buildings . It was a mixture of naphthenic acid and palmitic acid and the name was derived from the first syllable of each acid. (Fig. 1)(Ref. 1)

By the time of the Vietnam War, napalm was made using a mixture of plastic polystyrene, benzene and gasoline.  It creates a jelly-like substance and when ignited,sticks to everything, burning up in ten minutes. (Ref. 2) (Fig.1)

The chemical reaction is quite simple. Gasoline alone can get ignited and burn/ oxidize, but the addition of benzene (inflammable material) and a plastic allows longer burning , sticking to the clothes and skin, and in addition, the carbon dioxide formed when any hydrocarbon burns, (see Week 8) is actually converted to carbon monoxide because of incomplete combustion.  This adds to lack of oxygen and death due to difficulty breathing.

Man has always looked for  chemical weapons during war.  Before World War 2, mustard gas was used in World War 1.  The structure is shown in Fig. 1; a four carbon hydrocarbon with sulfur, S, in the middle and two chlorine , Cl atoms, one at each end. (Ref. 3)

Mustard gas, is chemically known as 1,1, thio bis (2-chloro ethane).  ‘ Thio’ is for the sulfur and ‘bis’ implies 2 pieces of 2 carbon atoms, viz.,ethane each having a chlorine atom. (Fig. 1)

The chemical reaction steps of how mustard gas reacts on the human body is shown here:

Mustard gas converts due to nucleophilic attack of carbon by the sulfide to a sulfonium salt; this is attacked by water present as moisture in the human body to a hemi mustard and HCl, hydrochloride acid.  This is attacked by water to form a Thio- glycol plus HCl, and the final step has HCl once more as a by-product. Mustard gas and hemi- mustard are vesicants and the three molecules of HCl is also a strong skin irritant. (Ref. 4)

The next war weapon we will look at is White Phosphorus.  It is actually a polyatomic molecule, having four P atoms in a tetrahedral arrangement.  It is one of the three allotropes of Phosporus. (Week 17)(Fig. 1)

White Phosphorus has been used several times in war as a chemical weapon.  It is considered illegal to use this as a weapon of war. Originally, though, in World War 1, it was used as a smoke screen and for flares.  However, in the late 20th century and early 21st century, USA, Russia and Israel have been accused of illegal use. (Ref. 5)

White Phosphorus oxidizes in the presence of oxygen to form phosphorus pentoxide. (Week 17)  This oxide is extremely hygroscopic, which means it absorbs moisture very readily.  If it comes into contact with skin, it will definitely cause severe blisters. It is difficult to extinguish and keeps on burning as long as oxygen is present. (Ref. 5)  One can only imagine the horrible burns and death it can cause.

The ancient Mayas had a noble tradition, whereby they gave their enemies a decent burial. But the human race now with the use of chemical weapons like napalm,mustard gas and white phosphorus, to name only a few, are intent on bringing cruel and inhumane ways of attacking the enemy which many times includes innocent civilians.

Activities for Middle School Teachers:

Let students do a time line of chemical agents used in war.  What kinds of  such weapons were used besides vesicants and napalm?

Study how many of these chemical weapons contain chlorine.  How many contain sulfur?  What, if any is the most common element or group of elements found  in these chemical weapons?

Besides chemical weapons, there has been biological weapons used, let students make a list of these war agents as well.  How do they cause harm to humans?

Nuggets of Information: 

Dr. Louis F. Fieser created an aluminium soap mixed with naphthenic and palmitic acid.  The name napalm came from the first syllables of the two acids. This combined with gasoline, was a brutally effective weapon. (Fig. 1)(Ref. 1)

In World War 2, the German word “bombenbrandscrumpfeichen” was created in response to napalm bombing of German bunkers. Soldiers in the bunkers would be baked by the heat and the word means ” firebomb shrunken flesh”. (Ref. 1)

Kurt Vonegut’s book, Slaughterhouse Five, is about a controversial campaign where 35,000 to 135,000 German soldiers died due to napalm in World War 2. (Ref. 1)

During the Vietnam War, napalm (b) was formulated that caused even more terrible destruction of soldiers and civilians. (Ref.1)(Fig. 1)

That terrified little girl from the first paragraph, Kim Phuc, survived miraculously and is today a U.N.Goodwill Ambassador. (Ref.1)

But napalm may still have been used, despite protests and bans by the U.N., during the Persian Gulf War by U.S. forces. (Ref. 1)

Mustard gas is a vessicant, which means an agent that induces blistering. (Ref. 6)

Though this gas is always seen as a nasty poison, resulting in a slow, painful death and causes cancer, yet, ironically, it has also been used to treat cancer!  In 1919, after the first usage of mustard gas,it was noted that victims had a low blood cell count.  In 1946, nitrogen mustards (replace sulfur,S, by a nitrogen,N) reduced tumor growth in mice as well as humans.  Now nitrogen mustards have become a modern chemotherapy therapy treatment for lymph glands Hodgkin’s Disease. (Ref. 4)

White Phosphorus was also called Willie Peat during  World War 1. (Ref. 5)

image

  References:

1. science.howstuffworks.com (put in ‘napalm’ in search line)

2.  vietnamawbb.weebly.com

3.  pubchem.ncbi.nih.gov

4.mhchem.org/221/COTW/mustard_gas/mustard.htm

5.wisegeek.com (put in ‘ white phosphorus’ in search line)

6.medical-dictionary.thefreedictionary.com (put in ‘vesicant’ in search line)

 

 

 

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