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THE ACTION OF REACTION

 

     Why something burns?  What is happening in a chemical reaction?  How the energy is liberated?

     To understand how the nature works, it has provided us some simple systems.  For example, the earth and the moon.  If we understand the mechanics of how the moon goes around the earth, we can understand the planetary system, stars and galaxies.  Similarly, the nature has given us a simplest atom, hydrogen.  It is just a single positive proton that is circled by single negative electron.

     The single electron is in the first orbit of  hydrogen.  If it gets one more electron, it will be stable.  Why?  Consider a giant wheel, if weights are distributed  evenly on the wheel, it will rotate smoothly with stability.  That means, all the seats in the giant wheel should be filled up.  Similarly, first orbit has two vacancy.  But the hydrogen has only one electron.  (Why the first orbit requires two electrons can only be explained clearly with quantum physics.)

     Now consider oxygen atom.  It has 8 electrons.  First orbit is filled up with 2 electrons.  Second orbit has only 6 electrons.  The quantum physics or octet rule says, the second orbit should have 8 electrons for completion and stability.  Hence the oxygen atom is always thirsty for 2 electrons.  Let us say, hydrogen atoms and oxygen atoms meet.  If you ignite them, they will burn down to water and release lot of light and heat energy.  What is happening?

     When H atoms and O atoms meet, oxygen gives one electron to each of H atom.  The two hydrogen atoms also give one electron each to the oxygen atom with gratitude.  Now there is two donated electrons between each H and O atoms..  These donated electrons become common property and shared by both the O and H atoms.  'This sharing of electrons' is called co-valent bond.  In short, oxygen makes co-valent bond with each of the two hydrogen atoms.  See figure . Now each H got 2 electrons and the O got 8 electrons in the second shell.  All the atoms feel happy and stable. [ That is why, there is no O and H gas.  But only O2 and H2 gas].  We now say H2O, the water molecule has formed.

     The revolving electrons have energies.  When it looses energy, it is always in the form of heat, light, UV rays. (simply, electromagnetic waves).  The total energy of electrons in the individual atoms (2H+1O) is always greater than the energy of molecular system H2O.  Hence there is a loss of energy. When water molecule is formed or co-valent bond is formed, that energy is released in the form fire, light and heat.  The equation for the reaction is,
     2H2+O2 = 2H2O + energy
     Loosing electrons is called Reduction.  Gaining electrons is called oxidation.

     The Redox reaction is the dominant reaction in chemistry.
    Our body is the factory of many chemical reactions.
    The drugs works because of chemical reactions.
     Cooking is also chemical reaction.     
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