Hydrogen+Peroxide

__**General:**__ Hydrogen peroxide is used as a disinfectant to clean cuts. It is a clear liquid and is usually a bleach or cleaning agent. Its molecular formula is H2O2. Almost all organisms have an enzyme called catalyse peroxidases which breaks down low amounts of hydrogen peroxide into water and oxygen.

Hydrogen peroxide also comes in a dark brown bottle so that no light can get in because if light gets in, it decreases its potency. It decreases in potency because the sunlight that would otherwise penetrate a clear bottle would break down the bonds which give the peroxide it's chemical structure.

__**History:**__ Hydrogen peroxide was originally discovered in 1818 by Louis Jacques Thénard and was considered unstable. The problem of insability was a result of impurities and in 1894 Richard Wolffenstein was able to create pure hydrogen peroxide.



=Hydrogen peroxide= Hydrogen peroxide is a chemical compound of hydrogen and oxygen. (It can be thought of as water with an extra oxygen atom.) Pure anhydrous hydrogen peroxide is a colorless, syrupy liquid that it rapidly decomposes into oxygen and water. Hydrogen peroxide is also a strong disinfectant cleanser and bleach. In nature, hydrogen peroxide is created in the atmosphere when ultraviolet rays strike oxygen in the presence of moisture. Ozone is free oxygen with an extra atom of oxygen. When ozone comes into contact with water, this extra atom of oxygen splits off easily. Water combines with the extra oxygen atom to become hydrogen peroxide.

Thenard's Studies
Louis Jacques Thenard (1777-1857), a French chemist, is credited with discovering hydrogen peroxide. One of the first things he found out about hydrogen peroxide is that it attacks the skin, producing painful blotches (fortunately, this effect wears off completely within a few hours). Thenard had tried for many months to formulate the chemical. At the time, however, scientists did not know how much oxygen could be combined with water. In 1818 Thenard finally succeeded in preparing pure hydrogen peroxide, which he called "oxygenated water," and determined its density. In addition to attacking the skin, the chemical also reacts explosively with metal oxides, as Thenard soon discovered. For several years afterward, he continued to study the compound, defining its properties and using it to prepare new peroxides (other compounds containing extra oxygen).

Multiple Uses
One of the first uses of hydrogen peroxide was to restore old paintings by removing sulfur compounds from their surface. Today hydrogen peroxide has found many more valuable applications, mainly in industry but also for medical purposes. Because the chemical is a strong oxidant (it combines with other compounds to produce oxides and water), it is widely used as a commercial bleaching agent in the production of cotton, wool, and delicate fabrics that would be destroyed by other agents. Even though it costs more than chlorine bleach, hydrogen peroxide is preferred in these applications because its action on fibers is milder and it leaves no undesirable residues. The chemical is also used cosmetically in hair bleach. In concentrated forms, hydrogen peroxide has found high-technology applications as a fuel additive for rockets, sumarines, and jet planes. In the computer industry, hydrogen peroxide has found widespread for washing transistors and integrated chip parts before assembly.

Dental and Medical Applications
Hydogen peroxide has numerous medical applications. It has long been used as an antiseptic to prevent infection and to cleanse and treat mouth sores. Today it is also used as a mouth wash and as a teeth whitener. The demand for whiter, brighter teeth became a booming business in the mid-1990s. More than a dozen products were introduced, all promising to fix yellow, stained teeth. Most of these whiteners rely on chemicals known as "oxygenating agents" to bleach teeth. The most common ingredient is a ten percent concentration of carbamide peroxide, which in contact with mouth fluids breaks down into hydrogen peroxide. This process also releases a highly reactive form of oxygen. Scientific studies have suggested that in some circumstances oxygenating agents can damage tissues and harm the pulp or interior of the teeth and even cause genetic mutations. For years hospitals have used high-pressure steam sterilizers. These machines require temperatures too hot for many sensitive insruments. In the 1950s, hospitals began using low-temperature sterilizers, but the process was time-consuming and relied on ethylene oxide, a carcinogenic (cancer-causing) gas. In 1996 a [|California] company, Advanced Sterilization, introduced a new instrument sterilizer for hospitals. The device is a low-temperature sterilizer fueled by a simple household chemical long used to fight infection: hydrogen peroxide.

First recognized as a [|chemical compound] in 1818, hydrogen peroxide is the simplest member of the class of [|peroxide]s. Of the several processes of manufacture, the principal ones involve reactions of oxygen from the [|air] with certain [|organic compounds], especially [|anthraquinone] or [|isopropyl alcohol]. Major commercial grades are aqueous solutions containing 35, 50, 70, or 90 percent hydrogen peroxide and small amounts of stabilizers (often tin salts and phosphates) to suppress decomposition. Hydrogen [|peroxide] decomposes into [|water] and oxygen upon heating or in the presence of numerous substances, particularly salts of such metals as iron, copper, manganese, nickel, or chromium. It combines with many compounds to form [|crystalline solids] useful as mild oxidizing agents; the best-known of these is [|sodium perborate] (NaBO 2 ·H 2 O 2 ·3H 2 O or NaBO 3 ·4H 2 O), used in laundry detergents and chlorine-free [|bleach] products. With certain organic compounds, hydrogen peroxide reacts to form hydroperoxides or peroxides, several of which are used to initiate polymerization reactions. In most of its reactions, hydrogen peroxide oxidizes other substances, although it is itself oxidized by a few compounds, such as [|potassium permanganate]. Pure hydrogen peroxide freezes at -0.43° C (+31.3° F) and boils at 150.2° C (302° F); it is denser than water and is soluble in it in all proportions.
 * hydrogen peroxide ****,** (H 2 O 2 ), a colourless [|liquid] usually produced as aqueous solutions of various strengths, used principally for bleaching cotton and other textiles and [|wood pulp], in the manufacture of other chemicals, as a [|rocket] [|propellant], and for cosmetic and medicinal purposes. Solutions containing more than about 8 percent hydrogen peroxide are corrosive to the skin.

Safety
Regulations vary, but low concentrations, such as 3%, are widely available and legal to buy for medical use. Most over-the-counter peroxide solutions are not suitable for ingestion. Higher concentrations may be considered hazardous and are typically accompanied by a Material Safety Data Sheet (MSDS). In high concentrations, hydrogen peroxide is an aggressive oxidizer and will corrode many materials, including human skin. In the presence of a reducing agent, high concentrations of H2O2 will react violently. High-concentration hydrogen peroxide streams, typically above 40%, should be considered a D001 hazardous waste, due to concentrated hydrogen peroxide's meeting the definition of a DOT oxidizer according to U.S. regulations, if released into the environment. The EPA Reportable Quantity (RQ) for D001 hazardous wastes is 100 pounds (45 kg), or approximately 10 US gallons (38 L), of concentrated hydrogen peroxide. Hydrogen peroxide should be stored in a cool, dry, well-ventilated area and away from any flammable or combustible substances. It should be stored in a container composed of non-reactive materials such as stainless steel or glass (other materials including some plastics and aluminium alloys may also be suitable). Because it breaks down quickly when exposed to light, it should be stored in an opaque container, and pharmaceutical formulations typically come in brown bottles that filter out light