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Chemistry (Important facts-1) – HPExams.in
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Chemistry (Important facts-1)

  • A substance that is used for the removal of excess of chlorine after the bleaching of a substance by chlorine is called antichlor.
  • Aquaregia is mixture of one part nitric acid and three parts of hydrochloric acid.
  • The number of molecules present in one gm mole is called Avogadro’s number. It is equal to 6.023 x 10²³
  • Sodium Bicarbonate is also called baking soda.
  • Sodium Carbonate (Na2CO310H2O) is commonly called washing soda.
  • Sodium Sulphate (Na2SO410H2O) is commonly called Glauber’s salt.
  • Impure copper having blisters on its surface is called Blister copper.
  • Buffer solution-A solution which prevents the change in pH of some other solution.
  • Carbohydrate -Organic compound with a general formula Cx(H20)x. They form important component of food.
  • Protein – Nitrogenous compounds which are the important constituent of living beings and plants. They are formed from amino acids.
  • A chemical substance that changes the rate of a chemical reaction,without itself undergoing any change is called a catalyst.
  • A substance formed by a fixed ratio of two or more elements is called a compound.
  • Constituents of a mixture can be separated by physical methods.
  • No chemical reaction takes place in a physical change, i.e., no new substance is formed.
  • There are 18 groups and 7 periods in the Long form of Periodic Table.
  • Atomic number was discovered by Moseley. The number of protons and electrons present in an atom is equal.
  • Group number in the Mendeleef’s Periodic Table represents the valency of elements present in that group.
  • The elements of I-A Group are called alkali metals (Li, Na, K,Rb, Cs and Fr).
  • The elements of I-B Group are called coinage metals (Cu, Ag,Au).
  • Mercury is also called quick silver.
  • Calcium oxide (CaO) is commonly called quick lime.
  • Pb,O, is also called Red lead.
  • Chemical composition of rust is Fe2O3xH2O.
  • Sodium carbonate is called soda ash or sal soda.
  • Nitrous oxide (N20) is called laughing gas.
  • Chemical formula of marble is CACO3.
  • NH3, CO, and C,F2CI2 are used as refrigerant.
  • Sodium silicate (Na2SiO3) is called water glass.
  • The alcoholic solution of iodine is called iodine tincture.
  • Formic acid is obtained from red ants.
  • Rold Gold contains 90% copper and 10% aluminium.
  • German silver contains 60% copper, 25% zinc and 15% nickel.
  • The mixture of benzene, petrol and ethyl alcohol is called power alcohol.
  • Fluorine is the most electronegative element.
  • Francium is the most electropositive element.
  • Silver is the best conductor of electricity.
  • Graphite is a non-metal which is the best electrical conductor.
  • Chlorine exhibits highest electron affinity.
  • Platinum is also called white gold.
  • Astatine (At) is the most rare element on earth.
  • Oxygen is the most abundantly found element on earth.
  • Nitrogen is most abundantly found in atmosphere.
  • Petrol is called liquid gold.
  • 24 carat gold is called pure gold.
  • Substances which undergo sublimation on heating-iodine, naphthalene, camphor, ammonium chloride and phthalic acid.
  • The nucleus of only hydrogen atom does not contain neutron.
  • Gold, platinum, mercury and silver are noble metals.
  • Lithium is the lightest metal.
  • Radon is the heaviest gas.
  • Astatine is the heaviest element among solid non-metals.
  • Lithium is the strongest reducing agent.
  • Atom bomb is based upon nuclear fission.
  • Hydrogen bomb is based upon nuclear fusion.
  • Solid carbon dioxide is called dry ice.
  • Only hydrogen is an element whose all the isotopes are named differently (Protium, deuterium and tritium).
  • Thermal decomposition of alkanes is called cracking.
  • Alpha (a) particle is equivalent to helium nucleus.
  • Beta (B) particle is equivalent to electron.
  • Diamond is the hardest element found in nature.
  • Polonium (Po) has largest number of isotopes (27).
  • Sulphuric acid is called oil of vitriol.

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