MONTREAL PROTOCOL: The Montreal Protocol on Substances That Deplete the Ozone Layer (a protocol to the Vienna Convention for the Protection of the Ozone Layer) is an international treaty designed to protect theozone layer by phasing out the production of numerous substances believed to be responsible forozone depletion. The treaty was opened for signature on September 16‚ 1987‚ and entered into force on January 1‚ 1989‚ followed by a first meeting in Helsinki‚ May 1989. Since then‚ it has undergone
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ALCOHOLS Alcohols are compounds in which one or more hydrogen atoms in an alkane have been replaced by an -OH group. For the purposes of UK A level‚ we will only look at compounds containing one -OH group. For example: Primary alcohols In a primary (1°) alcohol‚ the carbon which carries the -OH group is only attached to one alkyl group Some examples of primary alcohols include: Secondary alcohols In a secondary (2°) alcohol‚ the carbon with the -OH group attached is joined directly to
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ELECTRONEGATIVITY This page explains what electronegativity is‚ and how and why it varies around the Periodic Table. It looks at the way that electronegativity differences affect bond type and explains what is meant by polar bonds and polar molecules. If you are interested in electronegativity in an organic chemistry context‚ you will find a link at the bottom of this page. What is electronegativity Definition Electronegativity is a measure of the tendency of an atom to attract a bonding pair
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be eliminated or destroyed‚ and thus were soon advised to clean wounds and apply remedies as soon as soldiers showed signs of disease.18 Some physicians discovered the use of bromine as a sanitizing agent. William Hammond found that bromine “prevented sloughing”19 after amputations; Middleton Goldsmith placed bottles of bromine in each of the wards‚ and noted that “within 24 hours [he] saw a marked change for the better in all the patients since not one had died in the barracks from this disease except
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163 CHAPTER 13 HYDROCARBON Hydrocarbons are composed of Carbon and hydrogen. The important fuels like Petrol‚ kerosene‚ coal gas‚ CNG‚ LPG etc. are all hydrocarbons or their mixture. Sources: Petroleum and natural gas are the major sources of aliphatic hydrocarbon while coal is an important source of aromatic hydrocarbons. The oil trapped inside the rocks is known as petroleum. PETRA – ROCK‚ OLEUM – OIL. The oil in the petroleum field is covered with a gaseous mixture known as natural
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Relative Reactivity of Anilines Abstract: Various Anilines were tested with Br2/HBr solution‚ the products were crystallized and melting points attained to verify relative reactivity. My assignment‚ 2‚4-Dibromoanisol‚ was prepared in a yield of 52% with a melting point of 55-58 C . Reaction: Mechanism: Procedure: Anisole (0.35mL‚ 0.0378mol) was obtained and placed in a pre-weighed 25 mL round bottom flask‚ along with 2.5 mL of glacial acetic acid and a magnetic stir bar. Then the
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Elements classified as Metalloids The 7 elements classified as "Metalloids" are located in Groups 13‚ 14‚ 15‚ 16 and 17 elements of the Periodic Table. Elements classified as Metalloids have properties of both metals and non-metals. Some are semi-conductors and can carry an electrical charge making them useful in calculators and computers The Metalloids are: Boron Silicon Germanium Arsenic Antimony Tellurium Polonium Elements classified as Alkali Metals The 6 elements classified
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IGSCE Chemistry Notes Oxides Oxides are used to determine whether an element is a metal or a non-metal. Most non-metals are classed as acidic oxides. While most metals are classed as basicoxides. Acidic Oxides * Reacts with water to form acids * Neutralises alkaline solution to form salt + water Basic Oxides * Neutralises acidic solutions to form salt + water Amphoeteric Oxides * These are non-metals which display both acidic and basic properties Alkaline Oxides * Reacts
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decline of about 4% per decade in the total volume of ozone in Earth’sstratosphere (the ozone layer)‚ and a much larger springtime decrease in stratospheric ozone over Earth’s polar regions. The latter phenomenon is referred to as the ozone hole. In addition to these well-known stratospheric phenomena‚ there are also springtime polar tropospheric ozone depletion events. The details of polar ozone hole formation differ from that of mid-latitude thinning‚ but the most important process in both is catalytic destruction
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nitric acid to zinc granules adding concentrated sulphuric acid to solid sodium bromide adding concentrated sulphuric acid to magnesium adding iron(II) nitrate solution to acidified potassium permanganate solution adding sodium sulphite solution to bromine water adding hydrogen sulphide to acidified potassium dichromate solution adding oxygen to potassium iodide in alkaline medium to give iodine and hydroxide adding carbon to concentrated sulphuric acid adding copper to silver nitrate
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