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LAW OF CONSERVATION OF MASS,LAW OF DEFINITE PROPORTION, ILLUSTRATE EXAMPLE

Law of Conservation of Mass

           According to this law, during any physical or chemical change, the total mass of the products remains equal to the total mass of the reactants.
            
The law of conservation of mass is also known as the "law of indestructibility of matter."

Law of definite proportion

 Law of definite proportion, one of the laws of chemical composition can be defined as, Every compound always consists of the same elements present together in a fixed proportion by mass. Say, for example, 9 grams of water, irrespective of the source, or the method of preparation of the sample, yields 1 gram of hydrogen and 8 grams of Oxygen.
This law is most commonly known as Proust's law. His law formed the basis of Dalton's atomic theory.

Example : 1

    Let us consider any compound, say carbon dioxide.
    We know that it is made up of carbon and oxygen. Atomic mass of carbon is 12, while that of Oxygen is 16.
    So, basically, there are 12 grams of Carbon and 16 x 2 = 32 grams of Oxygen in carbon dioxide.
    The ratio of Carbon to oxygen would be: 12 : 32 = 6 : 16 = 3 : 8.
    The simple ratio is 3 : 8. So, taking any grams of CO2, it will always contain 3 parts of Carbon and 8 parts of Oxygen. This will remain a fixed ratio.
    If we take 50 grams of carbon dioxide, it will have

50 X 3/11 = 13.64 grams of Carbon and
50 x 8/11 = 36.36 grams of oxygen.

Example : 2

    Let us take the example of Ammonia. We know that ammonia has one nitrogen, so, 14 grams of N and 3 hydrogen, 3 grams of H.
    It will be in the ratio of: 14 : 3.
    So, if we have 50 grams of ammonia, it will contain

50 x 14 / 17 = 41.17 grams of Nitrogen and 50 x 3 / 17
= 8.82 grams of Hydrogen.


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