Dirigibles, hydrogen

The smoking salons of the Hindenburg and other hydrogen-filled dirigibles of Ihe 1930s were insulated with urea-formaldehyde polymer foams. The structure of this polymer is highly cross-linked, like that of Bakelite (Section 31.5). Propose a structure. 

Lighter-than-air balloons Hydrogen gas that is fighter than air was used to inflate some of the early free flight balloons and was used later in some dirigibles until the danger of explosions led to the use of helium as a substitute. 

Explosive burning of the hydrogen-filled dirigible Hindenburg during landing at Lakehurst, New Jersey, on May 6,1937, killed 36 of the 97 persons aboard. 

Calculate the area of solar collection necessary to power a 300-kW lighter-than-air vehicle by means of photovoltaic cells (20% efficient), electrolyzing onboard water. Assume a 200-m-long dirigible (as an approximation, take its shape as cylindrical with a radius of 20 m). Could a hydrogen-lifted vehicle be solar powered but fly during darkness (Bockris)... 

What property of hydrogen makes it less desirable than helium for inflating balloons and dirigibles ... 

Helium is also used to inflate balloons and other lighter-than-air craft, such as dirigibles (blimps). Helium does not have the lifting power of hydrogen. However, hydrogen is flammable and helium is not. 

The Hindenburg, a hydrogen-filled dirigible, explodes during a landing in Lakehurst New Jersey. 

Hydrogen is no longer used in blimps and dirigibles. It has been replaced by helium, which is slightly denser, nonflammable, and much safer. 

It should also be remembered that the Hindenburg and its sister dirigibles were designed to be inflated with non-flammable helium. Hydrogen had to be substituted when the United States, the sole source, refused to sell helium to the Germans in the aftermath of World War I. 

A chemical explosion is in essence a reaction that is complete in a very short time and produces a lot of energy. In Chernobyl and Ftrkushima, this was the well know hydrogen-oxygen explosiort, which also caused the tragedy of the Hindenburg dirigible on 6 May 1937 ... 

But then antisocial behavior seems to have been common among pneumatic chemists, as evidenced by our next chemist, Henry Cavendish. Cavendish was the first to study hydrogen, the infamous gas of the Hindenberg dirigible explosion. Cavendish calmly calls it his inflammable air. 

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