How to prove the conditions for a real gas to be ideal?

Asked by tinku4121999 | 17th Sep, 2015, 08:03: PM

Expert Answer:

  • Gases show deviation from ideal behaviour because of two faulty assumptions:   
    • There is no force of attraction between the molecules of a gas.
    • Volume of the molecules of a gas is negligibly small in comparison to the space occupied by the gas.
  • At low temperature and high pressure, gases deviate from ideal behaviour, i.e. gases behave as real gases.
  • At low pressure and high temperature gases show ideal behaviour, i.e. gases behave as ideal gases.
  • Plot of pressure–volume (pV) versus pressure (p) at constant temperature for ideal and real gases.

  • Plot of pressure (p) versus volume (V) for ideal and real gases.
  • Van der Waals equation of state is given below:
  • The deviation from ideal behaviour can be measured in terms of the compressibility factor Z, which is the ratio of product pV and nRT.

  • The deviations from ideal behavior become less and less with increase in temperature.
  • The temperature at which a real gas obeys ideal gas law over an appreciable range of pressure is called Boyle temperature or Boyle point.

Answered by Prachi Sawant | 18th Sep, 2015, 09:27: AM