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EQUIVALENT MASS

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  EQUIVALENT MASS  Equivalent mass of a substance is the number of parts by mass of a substance which combines with 1.008 parts by mass of hydrogen,8 parts by mass of oxygen. Equivalent mass of an element=Atomic mass/valency EQUIVALENT MASS OF ACID   Equivalent mass of an acid is the number of parts by mass of it which can supply one part by mass of replaceable hydrogen. 1 gram equivalent mass of an acid is that mass of it which contains one gram equivalent mass of replaceable hydrogen atom. Equivalent mass of acid = molecular mass /basicity Eg-(I) The numberof replaceable hydrogen atoms in HCl is 1. Thus ,the basicity of HCl is 1 or is it monobasic.                    (ii)The basicity of H2SO4 is 2,since it contains 2 replaceable H2 atom,so it is called dibasic.   EQUIVALENT MASS OF A BASE Equivalent mass of base is that mass of it which can neutralise 1 gram equivalent mass of the acid. Eg:-The no.of hydroxyl group ...
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MODERN ATOMIC THEORY

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(I) Atoms are composed of still smaller particles which are called electrons, protons and neutrons. (II) Atoms of the same elements may not be similar in all respect. (III) Atoms of the different elements may have the same atomic masses. (IV) Atoms of the different elements may not combine in simple ratio. (V) Atoms of one elements can be changed into atoms of other elements. ATOMIC MASS        The atomic mass of an element is the average relating mass of an atom of the element as compared to the mass of c-twelve atoms taken as twelve unit.              1 any = 1.66056 × 10(power of -24) g Atomic mass= mass of atom of the element/mass of 1/12 atoms of the carbon GRAM ATOMIC MASS        It can be defined as, the mass of one mole of atom of a particular elements. Eg:- The atomic mass of oxygen is 16 amu. Therefore,one gram of oxygen is equal to gram atomic mass of oxygen. Number of gram atom=mass in gram/gram atomi...
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DALTON'S & MODERN ATOMIC THEORY

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DALTON'S ATOMIC THEORY                                              In the year 1808 John Dalton proposed a theory on the nature of matter. It stated that,all matters are made up of small individual particles known as atom. (I) Postulates of Dalton's atomic theory Matter is made up of very small individual particles called atom. Atoms of the same elements are indentical in all respect. Atoms can neither be created nor destroyed,also it cannot be divided into small particles. Atoms can be rearranged,combined or separated in chemical reaction. (ii) Limitations of Dalton's atomic theory  It doesn't explain the cause of chemical combination. It fails to explain gaseous volume. It doesn't give the ideas of isotopes and isobars. It doesn't give any ideas about the structure of atom. This theory doesn't account for allotropes. MODERN ATOMIC THEORY (1) Atoms are composed still...
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LAW OF CHEMICAL COMBINATION

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  1.LAW OF CONSERVATION OF MASS:- Matter can neither be created nor be destroyed as a result of any physical and chemical changes. The total mass of reactant is equal to the mass of the product. 2.LAW OD DEFINITE PROPORTION/CONSTANT PROPORTION:- According to the law, the chemical compoundare made up of elements that are present in a firx ratio by mass. e.g-Hydrogen and oxygen in a fixed massed ratio are present in a pure water in the ration of 1:8. 3.LAW OF MULTIPLE PROPORTION:- This was proposed by John Dalton. According to this law of multiple proportion, it States that if two elements form more than one compounds,then the ratio of the masses of the second element which combines with a fixed mass of the first element will always be the ratio of small whole numbers. 4.LAW OF RECIPROCAL PROPORTION:- This law states that if the two different elements combines separately with a fixed mass of third element, the ratio of the masses in which they combine with each other. 5.GAY-LUSSAC'S ...
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