HydrogenHydrogen is the most abundant element in the Galaxy. It is ten times as abundant than helium, which is the second most widely occurring element. On Earth it only makes up about 0.14 percent of the solid crust but is very very abundant in water molecules; oceans, ice packs, rivers, lakes, and water vapor inn the atmosphere. The amount of hydrogen in the Earth's atmosphere remains low because it is so light that it continually escapes into space.
Hydrogen is also part of the many organic carbon compounds present in animal and vegetable cells and organisms. Pure, molecular hydrogen is an odorless, tasteless, colorless gas. It is the smallest and lightest element, with the simplest atomic structure.
The name hydrogen comes from two Greek words meaning "maker of water."
HistoryLong before the science of chemistry, Paracelsus an alchemist, experimented with an inflammable gas that he produced by dissolving a metal in acid. The gas, hydrogen, however, was not recognized as a pure element until 1766. In that year Henry Cavendish, an English chemist showed that 'inflammable air', or 'phlogiston' as it was then called, was different from other combustible gases because of its density. Also in that year J. Warltire burned this new gas and found that water was produced.
Fifteen years later, Cavendish repeated Warltire's experiments and confirmed that water was formed when hydrogen was burned in oxygen. Antoine-Laurent Lavoisier, a French chemist, used the French word 'hydrogene' for this gas. Because of its simple structure, hydrogen, is often used as a model for studying atomic structure and more complex atoms.
Uses for HydrogenOnce upon a time, hydrogen was used to fill balloons and passenger-carrying airships. This lasted until World War II. The disaster of the Hindenberg, however, accelerated the switch to helium which has the advantage of non flammability.
Today, large amounts of hydrogen are used to make ammonia and methanol, to remove sulphur from petroleum fuels, and for stabilizing oil-refinery by-products. Hydrogen also is used in the manufacture, by hydrogenation, of food products such as margarine and vegetable shortenings.
In its liquid form hydrogen is used to produce extremely low temperatures. Liquid hydrogen is also important in space-exploration programs as a component of rocket fuel.