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 Aluminium

Aluminium is an ACCEPTOR atom, an impurity atom in a semiconductor, which can accept or take up one or more electrons from the crystal and become negatively charged.In semiconductor physics. It is a dopant atom that when added to a semiconductor can form a p-type region. For example, when silicon (SI), having four valence electrons, needs to be doped as a p-type semiconductor, elements from group III like boron (B) or aluminium (Al), having three valence electrons, can be used. The latter elements are also called trivalent impurities. Other trivalent dopants include INDIUM (In) and GALLIUM (Ga).

 Helium

Helium is USED to dilute the oxygen and NITROGEN to REDUCE these affects. Helium is the gas of CHOICE to use because it is an inert gas, is THINNER, therefore more compressible than air, and its narcotic properties are negligible in comparison to nitrogen.

 caffeine

Caffeine is the MAIN ACTIVE CONSTITUENT of TEA and COFFEE.

 Higher ATOMIC masses

Arsenic, beryllium, cadmium, CHROMIUM, LEAD, manganese, mercury, nickel, and SELENIUM are some of the metals called ‘heavy’ because of their high relative atomic mass. They persist in nature and can cause damage or death in animals, HUMANS, and plants even at very low concentrations.

 MONAZITE

The ORE which is FOUND in ABUNDANCE in INDIA is monazite.

 Helium

Trimix is a breathing gas, consisting of oxygen, helium and nitrogen, and is often used in deep commercial diving. The helium is included as a substitute for some of the nitrogen, to reduce the narcotic effect of the breathing gas at depth. It HELPS to reduce nitrogen NARCOSIS and to avoid the dangers of oxygen TOXICITY. With a mixture of three gases, it is POSSIBLE to CREATE mixes suitable for different depths or purposes by adjusting the proportions of each gas.

 It is the lightest gas

Hydrogen is a chemical element with symbol H and atomic number 1. With an average atomic weight of 1.00794 u (1.007825 u for hydrogen-1), hydrogen is the lightest element and its monatomic form (H₁) is the most abundant chemical substance, constituting roughly 75% of the Universe’s baryonic mass. Nonremnant stars are mainly composed of hydrogen in its plasma state. Air is the name given to the atmosphere used in breathing and photosynthesis. Dry air CONTAINS roughly (by VOLUME) 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.039% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of WATER vapor, on average around 1%. Naturally occurring atomic hydrogen is rare on Earth because hydrogen readily forms covalent compounds with most elements and is present in the water MOLECULE and in most organic compounds.

 LEAD and antimony

Type metal, alloy of lead, antimony, and tin used to make type characters for printing. By varying the proportions of the metals, the desired properties are produced for DIFFERENT kinds of TYPECASTING and printing PROCESSES.

 Isoprene

Natural RUBBER, also called India rubber, latex, Amazonian rubber, caucho or caoutchouc, as INITIALLY produced, consists of POLYMERS of the organic compound isoprene, with minor IMPURITIES of other organic compounds, plus water.

 Sulphuric acid

Sulphuric acid is produced from sulfur, oxygen and water VIA the CONVENTIONAL contact process (DCDA) or the wet sulfuric acid process (WSA). Sulfuric acid can be produced in the laboratory by BURNING sulfur in air and dissolving the gas produced in a hydrogen peroxide SOLUTION.

 HYDROGEN

The amount of energy RELEASED increases with the number of bonds present in the CHEMICAL SUBSTANCE or fuel. That is because each bond has a certain amount of energy stored in it therefore the more bonds the more energy is stored and more energy is released if these bonds BREAK through combustion. Theoretical values of energy released per gram of fuel (in joules/ gram) are: Hydrogen: 142.5 KJ/g; Methane: 55.6 KJ/ g; Ethanol: 29.7 KJ/g; Butane: 49.6KJ/g.

 Ge

Zone refining is a very USEFUL METHOD to get metals with very high purity such as SILICON and GERMANIUM. It is also referred to as zone melting, FLOATING zone process, and travelling melting zone.

 SODIUM chloride contains hygroscopic impurities like magnesium chloride

Table salt is refined salt, which contains about 97 to 99 percent sodium chloride. It usually contains substances that MAKE it free-flowing (anticaking agents) such as sodium ALUMINOSILICATE or magnesium CARBONATE. Because of Hygroscopic nature of salt it become wet in rainy season as the salt absorbs moisture from environment.

 WATER and petrol are immiscible with each other and petrol which forms the upper layer CONTINUES to burn

As water is heavier than petrol therefore slips down permitting the petrol to RISE to the surface and CONTINUE to burn. Besides, the existing temperature is so high that the water poured on the fire evaporates even before it can extinguisher the fire. Thus the petrol fire cannot be extinguished by water.

 Antarctica

Ozone holes are formed in Antarctica and these are due to SPECIAL clouds that form in the stratosphere CALLED polar STRATOSPHERIC clouds. Clouds usually do not form in stratosphere, this can happen only at such LOW temperatures. These clouds accumulate pollutants resulting in FORMATION of ozone holes.

 High INFLAMMABLE energy

Baryllium sulfate (BeSO₄) is a white crystalline solid. It was first isolated in 1815 by Jons Jakob Berzelius. Beryllium sulfate may be prepared by TREATING an aqueous solution of any beryllium salt with sulfuric acid, followed by evaporation of the solution and crystallization. The HYDRATED product may be converted to anhydrous salt by heating at 400°C. Baryllium Sulphate is less soluble in water due to High inflammable energy.

 hydrogen

Hydrogenation - to treat with hydrogen - is a chemical REACTION between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst. The PROCESS is COMMONLY employed to reduce or saturate organic compounds. The largest scale application of hydrogenation is for the PROCESSING of vegetable oils (fats to give margarine and related spreads and shortenings). Typical vegetable oils are derived from polyunsaturated fatty acids (containing more than one carbon-carbon double bonds). Their partial hydrogenation REDUCES most but not all, of these carbon-carbon double bonds. Hydrogenation converts liquid vegetable oils into solid or semi-solid fats, such as those present in margarine.

 Erythrocyte

Mammalian erythrocytes are unique among the vertebrates as they are non-nucleated CELLS in their mature form. These cells have nuclei during early phases of erythropoiesis, but EXTRUDE them during development as they mature in order to provide more space for hemoglobin. In mammals, erythrocytes ALSO lose all other cellular organelles such as their mitochondria, GOLGI apparatus and endoplasmic RETICULUM.

 1.0

The 1959 WHO International Standards for Drinking Water suggested that concentrations of COPPER greater than 1.5 mg/litre would MARKEDLY IMPAIR the potability of the water. However, in the first edition of the Guidelines for Drinking Water Quality, published in 1984, a guideline value of 1.0 mg/litre was ESTABLISHED for copper, BASED on its laundry and other staining properties.

 Sodium Benzoate

Sodium benzoate is a preservative. It is BACTERIOSTATIC and fungistatic under acidic conditions. It is most WIDELY used in acidic foods such as SALAD dressings (vinegar), CARBONATED drinks (carbonic acid), jams and fruit juices (citric acid), pickles (vinegar), and condiments. It is also used as a preservative in medicines and COSMETICS.

 Calcium CARBONATE EQUIVALENTS

Hardness of the water is COMMONLY measured in TERMS of calcium carbonate equivalents.

 H₂

Hydrogenation - to TREAT with hydrogen - is a CHEMICAL REACTION between molecular hydrogen (H₂) and another compound or element, usually in the presence of a catalyst. The largest scale application of hydrogenation is for the processing of vegetable oils (FATS to give margarine and related spreads and shortenings). Typical vegetable oils are derived from POLYUNSATURATED fatty acids (containing more than one carbon-carbon double bonds). Their partial hydrogenation reduces most but not all, of these carbon-carbon double bonds.

 4

The MAXIMUM number of isomers for an ALKENE with molecular FORMULA C₄H₈ is 4.

 WASHING SODA

Sodium CARBONATE is COMMONLY KNOWN as Washing Soda.

 Alum

Gypsum is ADDED in CALCULATED quantity in ORDER to adjust the rate of SETTING of cement. Alum is not PRESENT in cement.

 Oxygen

Oxygen has the HIGHEST percentage in both human BODY and on earth, but CARBON, the element with the second highest percentage in the body, is RELATIVELY rare on Earth.

 Calcium SULPHATE

Sulphur (as sulphate) is a major plant nutrient, and is ESSENTIAL for crop growth. Calcium Sulphate (gypsum) is used to improve soil QUALITY. Calcium sulphate acts as a pH BUFFER, which can contribute to neutralizing both soil alkalinity and acidity. It is mainly used for the reclamation of sodic SOILS through ion exchange (calcium replacing sodium).

 3

There are TWO HYDROGEN bonds between adenine and THYMINE (A=T) and three hydrogen bonds between CYTOSINE and guanine (G=C).

 Ozone

Ultraviolet RADIATION STRIKING the EARTH is DUE to the depletion of ozone.

 Dumas method

Duma's method can be used to ESTIMATE nitrogen in all type of organic compounds. Detection of nitrogen is done by Lassigne's TEST. ESTIMATION of PHOSPHORUS is done by CARIUS method.

 MADE cathode and a pure nickel red, the anode

Electroplating is the deposition by electrolysis of a coating of metal upon a conducting SURFACE. The simplest system makes the object to be PLATED the negative electrode (cathode) or plate in a galvanic couple. THUS a spoon or other object may be CONNECTED by a wire to a plate of nickel. The process that occurs on the spoon is called reduction and, therefore, the spoon is also referred to as a cathode.

 Faraday

Faraday's laws of electrolysis, in chemistry, are quantitative laws used to express MAGNITUDES of electrolytic EFFECTS, first described by the English SCIENTIST Michael Faraday in 1833.

 Formaldehyde in water

Embalming fluids USE formaldehyde as a PRESERVATIVE. Formaldehyde is the simplest ALDEHYDE with the CHEMICAL formula HCHO. Formalin is a solution of formaldehyde in water, USUALLY with a small amount of methanol added. It is widely used as an antiseptic, disinfectant and preservative for biological materials.

 Sulphur

In order to GIVE more STRENGTH and more ELASTICITY, natural rubber is heated with sulphur or sulphur compounds at 150°C TEMPERATURE. Vulcanized rubber has good tensile strength.

 STABLE half filled 2p sub level

Nitrogen has a half filled orbital. On the other HAND, since OXYGEN is already unstable RELATIVE to Nitrogen, by losing one electron it attains a stable half filled orbital. So oxygen undergoes IONISATION at a relatively lower energy. This is why nitrogen has a higher ionisation energy than oxygen.

 0.5 to 1.5 per cent carbon

The term hardened steel is often used for a medium or HIGH carbon steel that has been given the heat treatments of quenching followed by tempering. The quenching results in the formation of metastable martensite, the fraction of which is reduced to the desired amount during tempering. This is the most common STATE for finished articles such as tools and MACHINE parts. In contrast, the same steel composition in annealed state will be softer as REQUIRED for forming and machining. Carbon steels which can successfully UNDERGO heat-treatment have carbon content in the range of 0.30–1.70% by weight. Trace impurities of various other elements can have a significant effect on the quality of the resulting steel. Trace amounts of sulfur in particular make the steel red-short.

 WATER

In a FLAME of pure HYDROGEN gas, burning in air, the hydrogen (H₂) reacts with OXYGEN (O₂) to form water (H₂O) and releases heat.

 RAIN WATER

The PUREST FORM of water is rain water.

 Haemetite

Hematite, also SPELLED haematite, HEAVY and relatively HARD oxide mineral, ferric oxide (Fe₂O₃), that constitutes the most important iron ore because of its high iron content (70 percent) and its abundance. Its name is derived from the Greek word for “blood,” in allusion to its red colour. Many of the VARIOUS forms of hematite have separate names. The steel-gray crystals and coarse-grained varieties have a brilliant metallic lustre and are known as specular iron ore; thin scaly types are called micaceous hematite. Much hematite occurs in a soft, fine-grained, earthy form called red ochre or ruddle. Intermediate between these types are compact varieties, often with a reniform surface (kidney ore) or a fibrous structure (pencil ore). Red ochre is used as a paint pigment; a purified form, rouge, is used to polish plate glass. The most important deposits of hematite are sedimentary in origin. The world’s largest production (nearly 75 million tons of hematite annually) comes from a sedimentary deposit in the Lake Superior district in NORTH America.

 Water softening

Softening is the process of removing the dissolved calcium and magnesium SALTS that cause hardness in water. Water softening is achieved EITHER by adding chemicals that FORM INSOLUBLE PRECIPITATES or by ion exchange.

 Disinfectant

Bleaching powder, CaOCl₂ or calciumoxychloride is used to kill germs and BACTERIA of water because it CONTAINS chlorine element, which is good disinfecting AGENT.

 CH₄

Nature gas is 95 PERCENT METHANE (CH₄) plus four other hydrocarbons:
Ethane (C₂H₆) - 2.5 %, Propane (C₃H₈) - 0.2 %, Butane (C₄H₁₀) - 0.06%, Pentanes Plus (C₅H₁₂ + C₁₀H₂₂) -0.02%. It also contains small amounts of: NITROGEN (N₂) - 1.6%, Carbon Dixoide (CO₂) - 0.7%, Hydrogen Sulphide (H₂S) - TRACE, Water (H₂O) - trace.

 PEROXYACETYL nitrate

Peroxyacetyl nitrate is a secondary POLLUTANT present in photochemical smog. It is THERMALLY UNSTABLE and decomposes into peroxyethanoyl radicals and nitrogen dioxide gas. It is a LACHRYMATORY substance.

 Aluminium

Aluminium is not a POLLUTANT.

 None of the above

Natural pollution comes from natural sources like RELEASE of methane by cattle and paddy fields, carbon dioxide from plants and animals, DUST storms, nitrogen OXIDES, ozone, volcanic eruptions, emission of natural gas, sol erosion, ultraviolet rays,ETC. Mercury is not a cause of natural pollution.

 Terephthalic acid

Terylene is a CONDENSATION POLYMER of ETHYLENE glycol and terephthalic acid and also called POLYESTER.

 Polyamide polymer

Nylon threads are polyamides. They are the condensation POLYMERS of diamines and DIBASIC ACIDS.

 Polyamide

Nylon is a generic designation for a family of synthetic polymers, based on ALIPHATIC or semi-aromatic polyamides. Nylon is a thermoplastic silky MATERIAL that can be melt-processed into fibers, films, or shapes. It is made of REPEATING UNITS linked by amide links similar to the peptide bonds in proteins.

 Polyamide

Nylon is a GENERIC designation for a family of synthetic polymers, based on aliphatic or semi-aromatic POLYAMIDES. Nylon is a thermoplastic silky material that can be melt-processed into fibers, films, or shapes. It is made of REPEATING units linked by amide links similar to the peptide BONDS in proteins.

 Synthetic fibre

Terylene is the name for a synthetic polyester fibre. It is a synthetic polyester fibre or FABRIC based on terephthalic ACID, characterized by LIGHTNESS and crease resistance and USED for clothing, sheets, ropes, SAILS, etc.