Related to Kinetic Molecular theory!

  1. The derivation of the ideal-gas equation included the assumption that the number of molecules is very latge, so that we could compute the average force due to many collisions. However, the ideal-gas equation holds accurately only at low pressures, where the molecules are few and far between. Isn't this inconsistent?
  2. jcsd
  3. jtbell

    Staff: Mentor

    Experimentally, normal atmospheric pressure is low enough that the ideal gas law works well for many practical purposes at everyday temperatures.

    Using the ideal gas law, calculate the number of molecules in a 1 cm3 container at P = 1 atm and T = 20°C. Would you consider that to be a small number?

    Going further, if you assume a specific gas (e.g. nitrogen) you can use kinetic theory to calculate the number of molecular collisions against one wall of that container (1 cm2 assuming it's cubical). Again, would you consider that to be a small number?
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