Oxygen, uses

The amount of oxygen used in the degradation process is called the biochemical oxygen demand (BOD). A standard test has been devised to measure BOD in which the oxygen utilized by microorganisms in contact with the wastewater over a 5-day period at 20°C is measured. 

The oxygen used in the combustion is supplied by a small cylinder (120 Atm.) fitted with a pressure reduction valve, pressure gauge (to avoid the risk of the cylinder becoming exhausted during an actual determination) and fine control knob. It is important that the valve is kept free from oil or grease of any kind. In order to ensure the complete purity of the oxygen it is first passed through a purification train. 

C. Calculate the dipole moment of cyclopropenone using the OPTIONS input to change the 1.1 matrix element to 2.0 for electronegative oxygen. Use the results to infer the direction of the dipole moment toward or away from the oxygen atotn. 

Butane-Based Fixed-Bed Process Technology. Maleic anhydride is produced by reaction of butane with oxygen using the vanadium phosphoms oxide heterogeneous catalyst discussed earlier. The butane oxidation reaction to produce maleic anhydride is very exothermic. The main reaction by-products are carbon monoxide and carbon dioxide. Stoichiometries and heats of reaction for the three principal reactions are as follows ... 

Grade C, Type II is typical of Hquid oxygen used as a rocket propellant oxidizer. Particulate content is limited because of the critical clearances found in mechanical parts of the rocket engine. In addition to water, acetylene and methane are limited because, on long standing, oxygen evaporation could cause concentration of these combustible contaminants to reach hazardous levels. 

EDA, when heated with carbon dioxide under pressure (57), or treated with urea (58), or ethylene carbonate [96-49-1] (59), or CO and oxygen using a selenium catalyst (60), produces ethyleneurea. 

The replacement of rhodium from a wide range of rhodacycles to form condensed furans, thiophenes, selenophenes, tellurophenes and pyrroles has been widely explored and a range of examples is shown in Scheme 97. The rhodacycles are readily generated from the appropriate dialkyne and tris(triphenylphosphine)rhodium chloride. Replacement of the rhodium by sulfur, selenium or tellurium is effected by direct treatment with the element, replacement by oxygen using m-chloroperbenzoic acid and by nitrogen using nitrosobenzene. 

The oxidation requires 0.94 kg of oxygen. Using air, the quantities involved are... 

Oxygen used for eombustion oeeurs in the atmosphere. The ehemieal eomposition of air is approximately 21% oxygen and 79% nitrogen, or one part oxygen to four parts nitrogen. In other words, for eaeh eubie foot of oxygen eontained in the air, there are about four eubie feet of nitrogen. 

BOD test A procedure that measures the rate of oxygen use under controlled conditions of time and temperature. Standard test conditions include dark incubation at 20 C for a specified time (usually 5 days). 

Biochemical oxygen demand (BOD) The molecular oxygen used in meeting the metabolic needs of aerobic organisms in aqueous medium containing an oxidizable organic molecule. 

Hydrogen cyanide is a reactant in the production of acrylonitrile, methyl methacrylates (from acetone), adiponitrile, and sodium cyanide. It is also used to make oxamide, a long-lived fertilizer that releases nitrogen steadily over the vegetation period. Oxamide is produced by the reaction of hydrogen cyanide with water and oxygen using a copper nitrate catalyst at about 70°C and atmospheric pressure ... 

Similar to MTBE, TAME is used as gasoline additive for its high octane rating and its ability to reduce carbon monoxide and hydrocarbon exhaust emissions. Properties of oxygenates used as gasoline additives are shown in Table 5-2. °... 

Antioxidant agent Also called aging retardants. AOAs are of major importance to the plastic industry because they extend the plastic s (that are effected by oxygen) useful temperature range and service life during processing and/or product use. The variety of AOAs available and their specific uses are extensive. 

At PicArsn (Ref 19), the fast neutron activation approach for detection of expls in suitcases was extended to the activation of both nitrogen and oxygen using two 7-ray detector stations in sequence. After 14 MeV neutron irradiation, the baggage is first monitored for 6.1 MeV 7-rays from the l60(n,p),6N reaction (7.5 sec half-life), followed by measurement of the 10 min 13N. Because expls are also rich in oxygen and have characteristic ratios of N/O, it was felt that this approach would increase the probability of detection with a corresponding decrease in the false alarm rate... 

One reactant is sparingly soluble in the reaction phase and would be depleted were it not added continuously. Oxygen used in an aerobic fermentation is a typical example. 

Figure 3-14 shows a schematic view of an apparatus for combustion analysis. The stream of oxygen used to bum the substance carries the combustion products out of the reaction chamber and through a series of traps. Each trap is designed to collect just one combustion product. The mass of each trap is measured before and after combustion, and the difference is the mass of that particular product. 

C05-0135. Liquid oxygen, used in some large rockets, is produced by cooling dry air to -183 °C. How many liters of dry air at 25 °C and 750 torr would have to be processed to produce 150 L of liquid oxygen (density =1.14 g/mL) ... 

C12-0059. One of the reasons that different aquatic life-forms thrive in water of different temperatures is the variation with temperature in the concentration of dissolved oxygen. Using data in Table 12-2. calculate the percentage change in the equilibrium oxygen concentration when water warms from 0.0 °C to 25.0 °C. 

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