INTRODUCTION Waste is an unavoidable by-product of most human activity. Economic development and rising living standards in the Asian and Pacific Region have led to increases in the quantity and complexity of generated waste‚ whilst industrial diversification and the provision of expanded health-care facilities have added substantial quantities of industrial hazardous waste and biomedical waste into the waste stream with potentially severe environmental and human health consequences. Waste is
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because it uses electrons that have wavelengths about 100‚000 times shorter than visible light (photons)‚ and can achieve magnifications of up to 1‚000‚000x‚ whereas light microscopes are limited to 2000x magnification. The electron microscope uses electrostatic and electromagnetic "lenses" to control the electron beam and focus it to form an image. These lenses are analogous to‚ but different from the glass lenses of an optical microscope that form a magnified image by focusing light on or through the
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when atoms of chlorine and other halogens gain electrons ▪ ▪ ionic compounds= compounds composed of cations and anions ▪ ionic compounds are electrically neutral ▪ anions and cations attract one another by means of electrostatic force ▪ ionic bonds= electrostatic forces that hold ions together in ionic compounds ▪ chemical formula=shows the kinds and numbers of atoms in the smallest representative unit of a substance. (ex: NaCl) ▪ formula unit= lowest whole number ratio of
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Lesson 03.01: History of the Periodic Table Explain how scientific observations led to the development of‚ and changes to‚ the periodic table. -Dmitri Mendeleev- first periodic table‚ organized 63 known elements according to properties‚ organized into rows and columns and wrote name‚ mass‚ and chemical properties on each -Julius Lothar Meyer- independently worked in Germany‚ similar to Mendeleev -Henry Gwyn Jeffreys Moseley- Worked with Ernest Rutherford‚ experimented with 38 metals‚ he found
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ELECTRICITY I. DISCOVER OF ELECTRICITY About 600 B.C.‚ Thales‚ a Greek philosopher and scientist‚ observed that a piece of amber attracted small bits of “paper” or very thin wood shavings after it was rubbed with wool. He had discovered‚ in effect‚ static electricity. William Gilbert‚ an English scientist in the sixteenth century‚ found that many other different materials could be made to act like amber. Whenever these objects were rubbed against each other‚ they were able to attract each other
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Chemical bond From Wikipedia‚ the free encyclopedia A chemical bond is an attraction between atoms that allows the formation of chemical substances that contain two or more atoms. The bond is caused by the electrostatic force of attraction between opposite charges‚ either between electrons and nuclei‚ or as the result of a dipole attraction. The strength of chemical bonds varies considerably; there are "strong bonds" such ascovalent or ionic bonds and "weak bonds" such as dipole–dipole interactions
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BTL-1 Inventor : George Stibitz Builder: Bell Labs Operational: 1939 Retired: 1949 Cost :20‚000$ Size : 8’ x 5’ x1’ Technology: Relays‚ Teletype Memory: 2 Complex Numbers Program: Fixed‚ complex arithmetic calculator Speed: 02 operations per second Z3 Inventor: Konrad Zuse Builder : Konrad Zuse Operational : 1941 Retired: 1944(Destroyed) Cost: $6500 Size: Two 6’ x 3’ x1’ Memory racks Technology: Relays Memory : 64 22-bit floating point words Program: 35mm punched film Speed
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Nm2C-2 4πε0 Mass of electron me = 9.1 x 10-31 kg Mass of neutron mn = 1.675 x 10-27 kg Boltzmann’s constant k =1.381 x 10-23 JK-1 Avogadro’s number NA = 6.022 x 1023 mol-1 Radius of earth = 6400 km UNITS- 1. ELECTROSTATICS 2.CURRENT ELECTRICITY 3.MAGNETIC EFFECT OF CURRENT AND MAGNETISM 4. EMI & AC 5. EM Waves. Q.1 How is the relative permeability (µr) of a material related to its susceptibility (χm) ? 1 Q.2 A metallic wire 1 m in length is moving normally across
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two atoms. The atom which donates the electron is called cation which is a positive ion whereas the atom which gains the electron is called anion which is a negative ion. The opposite charge of cation and anion attract one another due to the electrostatic force which is formed between them. The formation of a ionic bond involves a metal and a non-metal. Thus it forms the ionic bond. (A) EXAMPLE OF IONIC BOND (1) Sodium Chloride Sodium chloride is an ionic compound formed by the reaction between
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Sulphonation – The Process Most electrophilic substitution reactions are irreversible but sulfonation is an exception. Treatment of benzene with "oleum" (a solution of SO3 in concentrated sulfuric acid) will give the sulfonic acid‚ the electrophilic species being sulfur trioxide which is Lewis acidic. Fig – 1 Sulphonation : Benzene equation The sulfonic acid can be converted back by treatment with hot aqueous acid. The reason for this reversibility is the fact that the Wheland intermediate is overall
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