Composition of air

Material Two 100 ml syringes, combustion tube, glass tub, small cylinder, glass plates, wood splint, glass cylinder with combustion spoon and stopper, ruler steel wool, phosphorus. 

Tip The solution of the phosphorus oxide in water can be checked using indicator solution or indicator paper. It is acidic due to the formation of phosphoric acid. 

Engida, T., Sileshi, Y. Concept Cartoons as a Strategy in Learning, Teaching and Assessment Chemistry. Addis Ababa, Ethiopia, 2004 

Puettschneider, M., Lueck, G. Die Rolle des Animismus bei der Vermittlung chemischer Sachverhalte. CHEMKON 11 (2004), 167 

Schloepke, W.-L Alchimistisches Denken und Schuelervorstellungen uber Stoffe und Reaktionen. Chim.did. 17 (1991), 5 

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Air is the source of six industrial gases, N2, O2. Ne, Ar, Kr and Xe. As the mass of the earth s atmosphere is approximately 5 X 10 million tonnes, the supply is unlimited and the annual industrial production, though vast, is insignificant by comparison. The composition of air at low altitudes is remarkably constant, the main variable component being water vapour which ranges from 4% by volume in tropical jungles to very low values in cold or arid climates. Other minor local variations result from volcanism or human activity. The main invariant part of the air has the following composition (% by volume, bp in parentheses) ... 

We thus come to the remarkable conclusion that, beyond doubt, Leeuwenhoek in his experiment with the fully closed tube had cultivated and seen genuine anaerobic bacteria, which would happen again only after 200 years, namely, about 1862 by Pasteur. That Leeuwenhoek, one hundred years before the discovery of oxygen and the composition of air, was not aware of the meaning of his observations is understandable. But the fact that in the closed tube he observed an increased gas pressure caused by fermentative bacteria and in addition saw the bacteria, prove in any case that he not only was a good observer, but also was able to design an experiment from which a conclusion could be drawn. 

Thus for answering a stinging question van Helmont performed a noteworthy adequate experiment, but he was unable to draw the correct conclusions from it because the prerequisites were lacking. It took more than 150 years of research in chemistry to explore the composition of air and the basic constituents of plants. 

Bender, M. L., T. Sowers, J.-M. Barnola, and J. Chappellaz, Changes in the 02/N2 Ratio of the Atmosphere during Recent Decades Reflected in the Composition of Air in the Firn at Vostok Station, Antarctica, Geophys. Res. Lett., 21, 189-192 (1994). 

In this first part, also, Lavoisier considers the subjects of oxidation, fermentation, putrefaction, the composition of air and water and of acids, bases, and salts in general. 

In addition to exploring the chemical identity of gases and the nature of chemical reactions, Joseph Gay-Lussac was one of the first balloonists. In one of his balloon flights to test hypotheses on the composition of air and the extent of Earths magnetic field, Gay-Lussac reached an altitude of7000 meters (23,000 feet). This record remained unbroken for the next 50 years. 

The composition of air passing through this membrane changes from 21 percent oxygen to up to 44 percent oxygen because the larger nitrogen molecules get left behind. 

Pope, Dykstra, and Edgar (34), in 1929, published three papers on the mechanism of the vapor phase oxidation of isomeric octanes. The flow method was used. n-Octane was burned in a mixture of oxygen and nitrogen approximating the composition of air. A chemiluminescence filled the tube with occasional flashes from end to end. The principal products were aldehydes, water, and carbon monoxide. Some carbon dioxide was produced also. 

In power plant practice, the practical source of oxygen is primarily air. which includes, along with the oxygen, a mixture of nitrogen, water vapor, and small amounts of inert gases, such as argon, neon, and helium. Data on the composition of air are given in Table 3. 

Air is used as a source of reactants for many chemical and physical processes the oxygen is used for combustion and respiration, and the nitrogen is used as a starting material for the production of ammonia. To treat these gases quantitatively, we need to know the composition of air and, in some applications, the partial pressures of the components. A certain sample, of dry air of total mass 1.00 g consists almost entirely of 0.76 g of nitrogen and 0.24 g of oxygen. Calculate the partial pressures of these gases when the total pressure is 1.00 atm. 

The composition of air has undergone a remarkable change since the birth of our planet 4.6 billion years ago. The gases in the atmosphere of the infant earth were mostly methane, ammonia and water vapour. How different these ingredients are from those of the invisible dish you prepared ... 

There was no free oxygen or nitrogen in the primitive atmosphere. How and why did the composition of air change ... 

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