Related to Kinetic Molecular theory

In summary, the ideal-gas equation is derived by assuming a large number of molecules and is only accurate at low pressures. However, the ideal gas law still works well at normal atmospheric pressure and everyday temperatures. Using this law, the number of molecules in a 1 cm3 container at P = 1 atm and T = 20°C can be calculated, which may or may not be considered a small number. Similarly, using kinetic theory and assuming a specific gas, the number of molecular collisions against one wall of the container can also be calculated, which may or may not be considered a small number.
  • #1
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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  • #2
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?
 

What is the Kinetic Molecular Theory?

The Kinetic Molecular Theory is a model used to explain the behavior of gases. It states that gases are made up of particles (molecules or atoms) that are in constant motion and that the temperature of a gas is directly related to the average kinetic energy of its particles.

What are the main assumptions of the Kinetic Molecular Theory?

The main assumptions of the Kinetic Molecular Theory are that gas particles are in constant, random motion; that there is no attraction or repulsion between the particles; and that the volume of the particles is negligible compared to the volume of the gas.

How does the Kinetic Molecular Theory explain gas pressure?

The Kinetic Molecular Theory explains gas pressure as the result of gas particles colliding with each other and with the walls of their container. The more collisions that occur, the higher the pressure of the gas.

What is the relationship between temperature and kinetic energy according to the Kinetic Molecular Theory?

The Kinetic Molecular Theory states that the temperature of a gas is directly proportional to the average kinetic energy of its particles. As the temperature increases, the particles move faster and have a higher average kinetic energy.

How does the Kinetic Molecular Theory account for the differences in behavior between gases, liquids, and solids?

The Kinetic Molecular Theory explains that the differences in behavior between gases, liquids, and solids are due to the strength of the intermolecular forces between their particles. In gases, the particles are far apart and have weak intermolecular forces, allowing them to move freely. In liquids, the particles are closer together and have slightly stronger intermolecular forces, leading to more restricted movement. In solids, the particles are tightly packed and have strong intermolecular forces, resulting in a fixed shape and volume.

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