Chemistry' elements

HYDROGEN:

H1.00794(7)Atomic number
1
Atomic mass
1.007825 g.mol -1
Electronegativity according to Pauling
2.1
Density
0.0899*10 -3 g.cm -3 at 20 °C
Melting point
- 259.2 °C
Boiling point
- 252.8 °C
Vanderwaals radius
0.12 nm
Ionic radius
0.208 (-1) nm
Isotopes
3
Electronic shell
1s1

First element in the periodic table. In normal conditions it’s a colourless, odourless and insipid gas, formed by diatomic molecules, H2. The hydrogen atom, symbol H, is formed by a nucleus with one unit of positive charge and one electron. Its atomic number is 1 and its atomic weight 1,00797 g/mol. It’s one of the main compounds of water and of all organic matter, and it’s widely spread not only in The Earth but also in the entire Universe. There are three hydrogen isotopes: protium, mass 1, found in more than 99,985% of the natural element; deuterium, mass 2, found in nature in 0.015% approximately, and tritium, mass 3, which appears in small quantities in nature, but can be artificially produced by various nuclear reactions.

Common hydrogen has a molecular weight of 2,01594 g. As a gas it has a density of 0.071 g/l at 0ºC and 1 atm. Its relative density, compared with that of the air, is 0.0695. Hydrogen is the most flammable of all the known substances. Hydrogen is slightly more soluble in organic solvents than in water. Many metals absorb hydrogen. Hydrogen absorption by steel can result in brittle steel, which leads to fails in the chemical process equipment.

The periodic table is now ubiquitous within the academic discipline of , providing an extremely useful framework to classify, systematize and compare all the many different forms of behavior. The table has also found wide application in physics, biology,, and industry. The current standard table contains 117 confirmed elements (while element 118has been synthesized, element The methods vary according to the oxidizer and the filtration methods used. The common oxidizers for years have been chemicals like chlorine and potassium permanganate. Ozone and hydrogen peroxide are more natural oxidizers that are gaining in popularity. Precipitated iron is most commonly filtered out with specially prepared media called Birm, Filter Ag, and Pyrolox. The old standby carbon is most frequently used to filter hydrogen sulfide, although carbon can also be very effective for filtering iron. A new specialty medium called Centaur, or "catalytic carbon," is designed to be more effective than standard carbon with both iron and hydrogen sulfide.
Our preferred oxidizer is plain old air. Air is a powerful treatment for both iron and hydrogen sulfide, and air systems have the great advantages of low cost, safety, reliability, effectiveness, and ease of installation. Aeration systems add no chemicals to your well water and you avoid on–going chemical expense. Aeration systems are relatively trouble-free and completely safe

Hydrogen sulfide gas is easily detected with your nose. Most people describe the odor as a "rotten egg" smell. You can smell it in amounts so small that standard tests won’t find it. It is most often evident in hot water, but you can usually smell it in cold water as well. Since it is a gas and it goes away quickly, it has be tested on site. This means you can’t send a sample to a lab for testing. Often an amount of hydrogen sulfide so small that a test will not detect it can present a really serious aesthetic problem with your water.
The lack of practical storage methods has hindered the more widespread use of hydrogen fuels, which are both renewable and environmentally clean. The most popular storage methods-liquid hydrogen and compressed hydrogen-require that the fuel be kept at extremely low temperatures or high pressures. But the University of Chicago's Wendy Mao and David Mao have formed icy materials made of molecular hydrogen that require less stringent temperature and pressure storage conditions.

David Mao noted that while petroleum-based fuels will eventually run out, the supply of hydrogen is limitless. "Hydrogen is the most abundant element in the universe," said David Mao, a Visiting Scientist in Geophysical Sciences at the University of Chicago. If the new method of storing hydrogen fuel works as expected, "that's going to change everyone's life in a big way," he said.

In the realm of planetary science, the study helps explain how some of Jupiter's moons could have incorporated hydrogen during their formation. Scientists once thought that the moons were incapable of retaining hydrogen during their formation. Now it appears that Callisto, Ganymede and especially Europa contain large quantities of water ice, which would require the presence of hydrogen. The hydrogen clathrates that the Maos synthesized in the laboratory could have formed naturally under the temperature and pressure conditions expected to prevail inside these Jovian moons, Wendy Mao said.

Oxygen

Atomic Number 8 Symbol O Atomic Weight 15.9994 Discovery Joseph Priestley; Scheele 1774. Electron Configuration [He]2s22p4 Word Origin Greek: oxys: sharp or acid and Greek: genes: born, former... 'acid former'. Isotopes Nine isotopes of oxygen are known. Natural oxygen is a mixture of three isotopes.

Oxygen gas is colorless, odorless, and tasteless. The liquid and solid forms are a pale blue color and are strongly paramagnetic. Oxygen supports combustion, combines with most elements, and is a component of hundreds of thousands of organic compounds. Ozone (O3), a highly active compound with a name derived from the Greek word for 'I smell', is formed by the action of an electrical discharge or ultraviolet light on oxygen
Oxygen was the atomic weight standard of comparison for the other elements until 1961 when the International Union of Pure and Applied Chemistry adopted carbon 12 as the new basis. It is the third most abundant element found in the sun and the earth, and it plays a part in the carbon-nitrogen cycle. Excited oxygen yields the bright red and yellow-green colors of the Aurora. Oxygen enrichment of steel blast furnaces accounts for the greatest use of the gas. Large quantities are used in making synthesis gas for ammonia, methanol, and ethylene oxide. It is also used as a bleach, for oxidizing oils, for oxy-acetylene welding, and for determining carbon content of steel and organic compounds. Plants and animals require oxygen for respiration. Hospitals frequently prescribe oxygen for patients. Approximately two thirds of the human body and nine tenths of the mass of water is oxygen
Scientists at the University of Illinois have discovered a new way to make water, and without the pop. Not only can they make water from unlikely starting materials, such as alcohols, their work could also lead to better catalysts and less expensive fuel cells.

"We found that unconventional metal hydrides can be used for a chemical process called oxygen reduction, which is an essential part of the process of making water," said Zachariah Heiden, a doctoral student and lead author of a paper accepted for publication in the Journal of the American Chemical Society, and posted on its Web site.

A water molecule (formally known as dihydrogen monoxide) is composed of two hydrogen atoms and one oxygen atom. But you can't simply take two hydrogen atoms and stick them onto an oxygen atom. The actual reaction to make water is a bit more complicated: 2H2 + O2 = 2H2O + Energy.
In English, the equation says: To produce two molecules of water (H2O), two molecules of diatomic hydrogen (H2) must be combined with one molecule of diatomic oxygen (O2). Energy will be released in the process.

Iron

Iron is best known as the metal that gave us weapons and tools, and whose ability by means of alloys and heat treatment to suit itself to every application makes it the primary metal of technology. The purpose of this article, however, is principally to explain in some detail two remarkable applications of iron, ferromagnetism and oxygen transport in the blood. The very similar cobalt and nickel will also be included.

Iron is the most freqently encountered metal in daily life, always in the form of manufactured objects, and usually covered with a protective coating or buried deep within the object. Concrete structures contain essential reinforcing iron; electrical machines, including transformers, depend on iron. Automobiles are mainly iron; "tin" cans are iron covered with thin coatings of tin or lacquer; fasteners, such as the nails and screws used in wooden construction, are usually iron. This list can easily be extended with a little thought.

Iron is an excellent and versatile material of construction--strong, tough, easily formed and worked, and, very importantly, cheap compared to the alternatives. Plastics give it competition, especially in products that must be manufactured at the lowest cost where strength and durability are not the primary concerns, such as modern American automobiles. Aluminium is a strong competitor where weight is a concern, as in aircraft. However, the versatility of iron-carbon alloys cannot be matched in any other material. Alloys with other metals, such as nickel, chromium and manganese, give further advantages. These steels can be tailored to nearly every demand, and are not significantly challenged as materials of construction.

Our discussion of the human body as a chemical system begins by answering the question, "What type of atoms does the body contain?" Of the more than 100 chemical elements known to scientists today, only a relatively small number of these elements are found in the human body. In fact, only 24 different elements are thought to be essential to the human body. (Other elements, such as mercury, are sometimes found in the body, but they do not perform any known essential or beneficial function.) The largest elemental components of the body, by mass, are oxygen (65%), carbon (18%), hydrogen (10%), and nitrogen (3%). The other elements in the body, such as calcium, phosphorus, iron, and copper, are known to physiologists as mineral elements and trace elements. Although these elements make up a much smaller percentage of the mass of the body than oxygen, carbon, hydrogen, and nitrogen, mineral and trace elements are vital to the body's proper functioning. These elements must be present in the body in the proper amounts, and they must be available to react with other elements to form critical molecules and participate in important chemical reactions. In this tutorial, we will describe the importance of one essential trace element in the body, iron. Although iron comprises only 0.008% of the body's mass (approximately 6 g for a 160-lb (75-kg) adult male), we cannot live without this important element in our bodies.

The more rugged American planes really should not suffer from structural failures exept on very rare occasions from very large weapons like the Mk108's....some of the more rugged American aircraft include Jug, Hellcat, Corsair, Avenger, P-40, Wildcat, B-26, B-17, P-61, and the Helldiver.Yes American planes were built with a different philosophy in mind and that philosophy is not accurately depicted in this game...large chunks of the plane could be missing without the plane suffering structural failure. The P&W may have been the most robust engine of the war...it would get my vote...the DM is poor and Oleg really aught to address it...the tail sections falling off, fires and the weakness of the radial specifically.In addition, I get the suspicion that planes losing control surfaces was probably a Russian thing...I just can't find any references to that occurring in American aircraft. Yes they would go into compressibility and then shake apart or lawdart into the ground, but not this pcs falling off without compressibility.

Bromine

At ambient temperature bromine is a brownish-red liquid. It has a similarly colored vapor with an offensive and suffocating odor. It is the only nonmetallic element that is liquid under ordinary conditions, it evaporates easily at standard temperature and pressures in a red vapor that has a strong disagreeable odor resembling that o fchlorine. Bromine is less active chemically than chlorine and fluorine but is more active than iodine ; its compounds are similar to those of the other halogens. Bromine is soluble in organic solvents and in water

The goal of the new activity is to improve understanding of CCMs and their underlying GCMs (General Circulation Models) through process-oriented validation. One outcome of this effort is expected to be improvements in how well CCMs represent physical, chemical, and dynamical processes. In addition, this effort will focus on understanding the ability of CCMs to reproduce past trends and variability and providing predictions from ensembles of long model runs. Achieving these goals will involve comparing CCM constituent distributions with (robust) relationships between constituent variables as found in observations. This effort is both a model-model and modeldata comparison exercise.At the Grainau workshop, a set of key diagnostics was definedfor evaluating CCM performance with respect to radiation, dynamics, transport, and stratospheric chemistry and microphysics