Mole concept

One gram atom of any element contains the same number of atoms and one gram molecule of any substance contains the same number of molecules. The value was found to be 6.022137 × 1023 The value generally used is 6.022 × 1023 . This is called Avogadro’s number or Avogadro’s constant (NA) Avogadro’s number may be defined …

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Physical quantities

​Physical properties are those which can be measured or observed without changing the identity or composition of the substance. For example :Mass ,volume, melting point ,boiling point. Chemical properties are those in which a chemical change in the substance occurs. The measurement of any physical quantity consists of two parts: a)The number b)The unit For …

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Classification of matter

​Matter is defined as anything that occupies space and possesses mass. Classification of matter 1)Physical classification a)Solid b)liquid c)Gases                  Solid                    Liquid                        Gases 1)They have fixed shape and volume They do not have fixed shape but have fixed volume They do not have fixed shape and volume 2)They cannot be compressed …

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Importance of chemistry

​Chemistry is defined as that branch of science deals with the study of composition, structure and properties of matter and the changes which the matter undergoes under different conditions and laws which govern these changes. Importance of chemistry 1)Supply of food 1)It has provided chemical fertilizers such as urea ,calcium superphosphate, sodium nitrate, Ammonium Sulphate …

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