Related to Kinetic Molecular theory

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SUMMARY

The discussion centers on the Kinetic Molecular Theory and its application to the ideal gas law, particularly the conditions under which the ideal-gas equation is valid. It is established that the ideal gas law is accurate at low pressures, such as normal atmospheric pressure, which is sufficient for practical applications at everyday temperatures. The calculation of the number of molecules in a 1 cm³ container at 1 atm and 20°C demonstrates that even at low pressures, the number of molecules is significant, contradicting the notion of a "small number." Additionally, using nitrogen as a specific gas, the discussion explores the calculation of molecular collisions against a wall of the container, further emphasizing the substantial number of interactions occurring.

PREREQUISITES
  • Kinetic Molecular Theory
  • Ideal Gas Law
  • Basic Thermodynamics
  • Gas Properties and Behavior
NEXT STEPS
  • Calculate molecular density using the ideal gas law for various gases.
  • Explore the implications of Kinetic Molecular Theory on gas behavior at high pressures.
  • Investigate the relationship between temperature, pressure, and molecular speed in gases.
  • Learn about real gas behavior and deviations from the ideal gas law using Van der Waals equation.
USEFUL FOR

Students of chemistry and physics, educators teaching gas laws, and researchers interested in thermodynamic properties of gases will benefit from this discussion.

Himanshu_6174
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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?
 
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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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