Fundamental properties of hydrogen

With the expected increasing significance of hydrogen as a universal chemical and as an energy vector, its physical and thermodynamic properties are undergoing extensive investigation. To provide a basis of understanding for the themes covered in the remainder of the book, this chapter briefly describes the fundamental properties of 

Named by a French chemist, Lavoisier, hydrogen (H) is the first chemical element of the periodic table of elements with an atomic number of one. At standard temperature and pressure, hydrogen is a colourless, tasteless, odourless and easily flammable gas. With its atomic mass of 1.00797 g/mol, hydrogen is the lightest element. The British scientist, Henry Cavendish, was the first to identify H as a distinct element in 1766, publishing precise values for its specific weight and density (NHA, 2007). 

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The fundamental properties of SCFs and their relation to organometallic catalysis have been reviewed extensively in recent years, and will not be re-iterated here [1, 7]. The term supercritical indicates that the substance used as reaction medium or solvent is heated and compressed beyond its critical temperature and pressure. For C02, which is the most widely used SCF in hydrogenation reactions, these values are Tc=31.04°C and pc=73.83 bar. Owing to the complex... 

Chapter 9 addresses the fundamental chemical and physical properties of hydrogen and how they play out when using hydrogen as vehicle fuel. 

Considerations of mechanism despite their difficulties are extremely valuable and productive. The discovery of the catalytic properties of hydrogen fluoride for condensation reactions came about from considering the mechanisms of certain organic reactions coupled with a knowledge of the chemical and physical properties of hydrogen fluoride. That fundamental acidity is involved in the catalytic properties of hydrogen fluoride is confirmed by the fact that hydrogen chloride under appropriate conditions can catalyze some of the same reactions (Simons and Hart, 81). 

A very good picture of some of the properties of hydrogen compounds can be obtained with the aid of an electrostatic model, but we must be careful not to conclude that all the hydrogen compounds are therefore ionic in character. In addition to NHS, there are two other nitrogen compounds, hydrazine H2NNH2 and hydroxylamine NH2OH, which have properties not fundamentally dissimilar to those of ammonia. It is not possible to devise a plausible electrostatic model for these compounds because of the bond between like atoms. In addition to water there is also the compound hydrogen... 

The risk to the public during consumer end use of hydrogen derives from the possibility of accidental fire and explosion, a direct consequence of the physical and chemical properties of hydrogen. These properties help to define the kinds of safety issues that must be addressed, the fundamental design goals for hydrogen systems, and the operational limitations of these systems. Table 9-1 summarizes the properties of hydrogen in contrast with those of other commonly used fuels. 

You felt if you were measuring the properties of hydrogen, the most fundamental nucleus, you just measure it and do it as well as you can. 

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