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Chemistry - Coal and Petroleum Introduction The resources, which are present in unlimited quantity in nature and are not likely to be exhausted by human activities, are known as  Inexhaustible Natural Resources . E.g. sunlight, air. The resources, which are present in limited quantity in nature and are likely to be exhausted by human activities, are known as  Exhaustible Natural Resources . E.g. forests, wildlife, minerals, coal, petroleum, natural gas etc. Exhaustible natural resources were formed from the dead remains of living organisms (fossils); therefore, these natural resources are also known as  fossil fuels . E.g. coal, petroleum and natural gas. Coal Coal is hard as stone and black in color. Coal is one of the fuels used to cook food. Coal is used in thermal power plants to produce electricity. Under high pressure and high temperature, the dead plants those got buried inside the Earth, got slowly converted into coal. Coal contains mainly ...

Classification Of  Elements Introduction There are about 115 elements have been known to us till today. Based on their properties, all the elements are arranged in order, known as periodic table. Johann Wolfgang Döbereiner, a German scientist, first attempted to arrange the elements in 1817. John Newlands, an English scientist, also attempted to arrange the then known elements (in 1866). John Newlands had followed the order of increasing atomic masses to arrange the elements. Newlands started with the element having the lowest atomic mass (such as hydrogen) and ended at thorium, which was the 56th element (at his time). Newlands’ arrangement of elements is known as “Law of Octaves,” as in his arrangement every eight element had the properties similar to that of the first. E.g. the properties of lithium and sodium were found to be the same. Sa (do) re (re) Ga (mi) Ma (fa) Pa (so) da (la) ni (ti) H Li Be B C N O F Na Mg Al Si P S Cl K Ca Cr Ti Mn Fe Co & N...

              15   SCIENCE MOST HARDEST QUESTIONS                                      THAT WILL PROVE YOU ARE DUMB HEY, So you think you are smart enough to answer this questions? I bet you will regret clicking this article in the first place- just kidding😃. But seriously this questions have been debated for years by different scientist the good news is some of this questions have been provided with satisfying answers. but the point is THESE QUESTIONS WILL BE OF GREAT HELP TO STUDENTS IN: helping them to think deeply improving their knowledge concerning science topics looking at science with a different perspective AND ABOVE ALL TO HUMBLE ANY FELLOW STUDENT WHO THINKS HE IS THE SMARTEST IN CLASS😉 PLEASE ENJOY Why is the sky blue? Why does the moon appear in the daytime? How much does the sky weigh? How much does the Earth wei...

Chemistry - Carbon and its Compounds Introduction Carbon plays very important roles for all living beings. The amount of carbon in the earth’s crust is merely 0.02%, which is available in the form of minerals such as carbonates, hydrogen-carbonates, coal, and petroleum. The presence of carbon in the atmosphere of the earth is 0.03%, in the form of carbon dioxide. Compounds of Carbon Almost all carbon compounds (except a few) are poor conductors of the electricity. The diamond and graphite both are formed by carbon atoms; however, the difference lies between them in the manner in which the carbon atoms are bonded to one another. In diamond, each atom of the carbon, is bonded to four other carbon atoms and form a rigid three-dimensional structure (see the image given below). In graphite, each atom of the carbon, is bonded to three other carbon atoms in the same plane, which gives a hexagonal array (see the image given below) − There is also difference in some physical structu...

Chemistry - Metals and Non-Metals 2 Introduction A solid material, which is typically hard, malleable, shiny, fusible, and ductile, is known as metals. E.g. iron, copper, aluminum, magnesium, sodium, lead, zinc, etc. Normally, metals have good electrical and thermal conductivity. Metals, in their pure state, have a shining surface, known as  metallic luster . Metals can be beaten into thin sheets; this property is known as  malleability . The property of metals to be drawn into the thin wires is known as  ductility . E.g. gold is the most ductile metal. Silver and copper are the best heat conductor. Non-Metals The non-metals are normally found in either solids or gases states. However, bromine is an exception that found in liquid state. Some of the major examples of non-metals are carbon, sulphur, iodine, oxygen, hydrogen, etc. Facts of Metals and Non-metals All metals exist in the solid form at room temperature, except mercury. Gallium and caesium have very l...

Materials: Metals and Non-Metals 1 Introduction The metals can be distinguished from the non-metals on the basis of their chemical and physical properties. The property of metals by which they can be beaten into thin sheets is known as  malleability . The property of metal by which it can be drawn into wires is known as  ductility . The metals are normally hard, malleable, lustrous, ductile, sonorous, and good conductors of heat and electricity. E.g. iron, copper, calcium, aluminum, magnesium, etc. The materials, which are not sonorous and are poor conductors of heat and electricity, are known as  non-metals . E.g. sulphur, carbon, oxygen, phosphorus, etc. Some metals, such as  sodium  and  potassium  are soft and can be cut with a knife. Mercury  is the only metal, which remains in liquid state at room temperature. When sulphur dioxide is dissolved in water, sulphurous acid is formed. Illustration - Sulphur dioxide (SO 2 ) + Water (H ...

Chemistry - Acids, Bases, and Salts Introduction We taste food sour and bitter, it is only because of presence of acids and bases respectively. Litmus Solution Litmus, which is extracted from lichen, has purple color (see the image given below), but the condition is when it is neither acidic nor basic, i.e. neutral. Litmus basically is a plant belongs to Thallophyta, and in chemical experiment, it is commonly used as an indicator. The substances, which odor changes in acidic or basic media, are known as  olfactory  indicators. Acid or Base in a Water Solution The hydrogen ions in HCl are produced because of the presence of water. Secondly, the separation of H +  ion from the HCl molecules cannot be done in the absence of water. The chemical formula is illustrated below HCl + H 2 O → H 3 O +  + Cl – Furthermore, hydrogen ions cannot exist alone, but they can exist in presence of water molecules. Therefore, hydrogen ions are shown as H + (aq) or hydronium i...

Chemistry - Chemical Reactions & Equations Introduction A process in which one or more chemical substances react with other chemical substance and converted to one or more different substances is known as chemical reaction. Chemical Equation A chemical equation is the symbolic demonstration of a chemical reaction; it is represented through symbols and formulae. E.g. Magnesium + Oxygen = Magnesium Oxide Mg   +   O 2   =   MgO The substances magnesium and oxygen are known as reactants and the result of reaction, i.e., magnesium oxide is known as product. Remember,  the total mass of the elements present in the products of a chemical reaction has to be equal to the total mass of the elements present in the reactants. The number of atoms of each element always remains same, before and after the chemical reaction. Types of Chemical Reaction Following are the major types of chemical reaction − Combination Reaction Decomposition Reaction Displacement Re...

Chemistry - Structure of the Atom Introduction By 1900, it was discovered that the atom was not a simple, indivisible particle, but rather it contains sub-atomic particles. J.J. Thomson  discovered the sub-atomic particle namely  ‘electron.’ J.J. Thomson was the first person who proposed a  model  for the structure of an atom. In 1886, E. Goldstein discovered the presence of new radiations in a gas discharge and named them  canal rays. Another positively charged sub-atomic particle was discovered with experiments of canal rays and named it  proton . Thomson’s Model of Atom Thomson proposed that an atom consists of a positively charged sphere and the electrons (negative charge) are embedded in it (as shown in the image given below). Further, Thomson said that the negative and positive charges are equal in magnitude. Thus, the atom as a whole is electrically neutral. Rutherford’s Model of Atom E. Rutherford is popular as the ‘Father’ of nuclear ph...