Postulates | Dalton’s Theory | Kinetic Theory of Gas |

Main Postulates of Dalton Theory

  1. All matters are composed of extremely small, indivisible and discrete particles called atoms.
  2. Atoms of same elements are identical in all respect.
  3. Atom donot undergo sub division during chemical reaction and atom can neither be created nor be destroyed by any chemical processes. Also, it cannot be transferred in to atom of other element. This is known as the principle of indistructibility.
  4. The combination of two or more atoms of diifferent elements in simple whole number ratio to give the compound atom is known as molecule.
  5. Combining masses of elements are the combining masses of atoms.
  6. Properties of elements are due to the properties of respective atoms.

Postulates of Kinetic Molecular Theory of Gas

  1. All the gases contains large number of minor particles called molecules.
  2. Volume of gas molecule is so small that can be neglected as compared to the total volume of the gas or volume of container.
  3. Gas molecules are in  rapid, random motion in all possible direction so, law of motion can be applied. Eg: Brownion motion
  4. The collisonbetween the gas molecules is perfectly elastic i.e. there is no  any loss of kinetic energy when they collide with each other and with the wall of container.
  5. Average kinetic energy is directly proportional to the temperature.
  6. The pressure of a gas is due to the continuous bombardment of wall of container.
  7. There is large space between large, there is no force of attraction and repulsion.
  8. There is no effect of gravity on the moment of gas molecules.

These postulates are applicable for ideal gases

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