White Phosphorus At 200 0 C example essay topic

Phosphorus, symbol P, reactive non-metallic element that is important to living organisms and has many industrial uses. The atomic number of phosphorus is 15, and its atomic weight is 30.974. Phosphorus is in group 15 (Va) of the periodic table. Phosphorus was discovered about 1669 by the German alchemist Hennig Brand in the course of experiments in which he attempted to prepare gold from silver. Phosphorus exists in three main allotropic (distinctly different) forms: ordinary (or white) phosphorus, red phosphorus, and black phosphorus. Of these, only white and red phosphorus are of commercial importance.

When freshly prepared, ordinary phosphorus is white, but it turns light yellow when exposed to sunlight. It is a crystalline, translucent, waxy solid, which glows faintly in moist air and is extremely poisonous. It ignites spontaneously in air at 34^0 C (93^0 F) and must be stored under water. It is insoluble in water, slightly soluble in organic solvents, and very soluble in carbon disulfide.

White phosphorus melts at 44.1^0 C (111.4^0 F) and boils at 280^0 C (536^0 F). When heated to between 230^0 and 300^0 C (446^0 and 572^0 F) in the absence of air, it is converted into the red form. Red phosphorus is a microcrystalline, non-poisonous powder. It sublimates (passes from the solid state directly to the gaseous state) at 416^0 C (781^0 F) and has a specific gravity of 2.34. Black phosphorus is made by heating white phosphorus at 200^0 C (392^0 F) at very high pressure. It has a specific gravity of 2.69.

Phosphorus is widely distributed in nature and ranks 11th in abundance among the elements in the crust of the earth. It does not occur in the free state but is found mostly as a phosphate, as in phosphate rock and apatite. It is also found in the combined state in all fertile soil and in many natural waters. The element is important in plant and animal physiology and is a constituent of all animal bones, in the form of calcium phosphate. Nitrogen is the primary nutrient for plant growth. Healthy green foliage and general plant vigor depend on it.

Phosphorus'. Most phosphorous compounds are trivalent or quinquevalent. Phosphorus combines readily with oxygen to form oxides, of which the most important are phosphorus oxide (P 2 O 3) and phosphoric oxide (P 2 O 5). Phosphorus oxide, a white crystalline solid, is used as a reducing agent. It is deliquescent? that is, the moisture in air dissolves it. The vapor is toxic.

Phosphoric oxide, a white, deliquescent, amorphous solid, sublimes at 250^0 C (482^0 F). It reacts with water to form phosphoric acid and is used as a drying agent. Phosphorus forms hydrides with hydrogen; the important hydride of phosphorus is PH 3, which is comparable to ammonia (NH 3), the hydride of nitrogen. All of the halogens combine directly with phosphorus to form halides, which are used in the preparation of halogen acids and organic compounds. The most important commercial compounds of phosphorus are phosphoric acid and the salts of phosphoric acid, called phosphates. The bulk of phosphorus-containing compounds are used as fertilizers.

Phosphorous compounds are also used in clarifying sugar solutions, weighing silk, and fireproofing, and in such alloys as phosphor bronze and phosphor copper. White phosphorus is used in the making of rat poison, and red phosphorus is used in matches. Yellow phosphorus is mainly used in the production of chemical industry. Phosphoric acid is a downstream product of yellow phosphorus. Its major derivatives include phosphoric acid, sodium tripolyphosphate, phosphorus trichloride, phosphorus penta sulfide, phosphorus pent-oxide, hexametaphosphate.

Almost all of the phosphorus in the body occurs as phosphate (phosphorus combined with four oxygen atoms), and most of the body's phosphate (85%) is located in the skeletal system, where it combines with calcium to give bones their hardness. The remaining amount (15%) exists in the cells of the body, where it plays an important role in the formation of key nucleic acids, such as DNA, and in the process by which the body turns food into energy (metabolism). The body regulates phosphate levels in the blood through the controlled release of parathyroid hormone (PTH) from the parathyroid gland and calcitonin from the thyroid gland. PTH keeps phosphate levels from becoming too high by stimulating the excretion of phosphate in urine and causing the release of calcium from bones (phosphate blood levels are inversely proportional to calcium blood levels). Calcitonin keeps phosphate blood levels in check by moving phosphates out of the blood and into the bone matrix to form a mineral salt with calcium. Most phosphorus imbalances develop gradually and are the result of other conditions or disorders, such as malnutrition, poor kidney function, or a malfunctioning gland.

Hypophosphatemia (low blood phosphate) has various causes. Hyperparathyroidism, a condition in which the parathyroid gland produces too much PTH, is one primary cause. Poor kidney function, in which the renal tubules do not adequately reabsorb phosphorus, can result in hypophosphatemia, as can overuse of diuretics, such as theophylline, and antacids containing aluminium hydroxide. Problems involving the intestinal absorption of phosphate, such as chronic diarrhea or a deficiency of Vitamin D (needed by the intestines to properly absorb phosphates) can cause the condition.

Malnutrition due to chronic alcoholism can result in an inadequate intake of phosphorus. Recovery from conditions such as diabetic keto acidosis or severe burns can provoke hypophosphatemia, since the body must use larger-than-normal amounts of phosphate. Respiratory ankylosis, brought on by hyperventilation, can also result in temporary hypophosphatemia. Symptoms generally occur only when phosphate levels have decreased profoundly. They include muscle weakness, tingling sensations, tremors, and bone weakness. Hypophosphatemia may also result in confusion and memory loss, seizures, and coma.

Hyperphosphatemia (high blood phosphate) also has various causes. It is most often caused by a decline in the normal excretion of phosphate in urine as a result of kidney failure or impaired function. Hypoparathyroidism, a condition in which the parathyroid gland does not produce enough PTH, or pseudoparathyroidism, a condition in which the kidneys lose their ability to respond to PTH, can also contribute to decreased phosphate excretion. Hyperphosphatemia can also result from the overuse of laxatives or enemas that contain phosphate. Hypocalcemia (abnormally low blood calcium) can cause phosphate blood levels to increase abnormally. A side effect of hyperphosphatemia is the formation of calcium-phosphate crystals in the blood and soft tissue.

Treatment of phosphorus imbalances focuses on correcting the underlying cause of the imbalance and restoring equilibrium. Treating the underlying condition may involve surgical removal of the parathyroid gland in the case of hypophosphatemia caused by hyperparathyroidism; initiating hormone therapy in cases of hyperphosphatemia caused by hypoparathyroidism; ceasing intake of drugs or medications that contribute to phosphorus imbalance; or instigating measures to restore proper kidney function. Phosphorus promotes strong root development and winter hardiness. It helps grass withstand environmental stress. Grass well supplied with phosphorus is less likely to become diseased. A farmer friend of mine keeps a sign in his office that reads, "Common sense is a basic ingredient of any sound decision".

(I always figured that sign was there to enlighten the rest of us, more than it was to remind him.) At the risk of sounding simplistic, a little common sense could go a long way toward alleviating the problem of phosphorus entering our streams and lakes, where it causes excessive plant growth that diminishes water quality. That common sense needs to be augmented with research, however, because what makes sense isn't always scientifically correct. Some of that research is yet to be done. There is a lot to learn about measuring the risk of phosphorus entering our streams and lakes.

For exampled scientists say we need new and different testing procedures for environmental questions.