e-gas

Molecular Motion and the Gas Law – How the Ideal Gas Law Relates to Molecular Motion

Description :
This page is designed to help you understand the ideal gas law based on the molecular motion of gases.

● For simplicity, gas molecules are assumed not to collide with each other, and all molecules are considered to have the same speed (in reality, gas molecules do collide and their speeds follow the Maxwell-Boltzmann distribution).
● Since molecules have kinetic energy proportional to the absolute temperature T, their speed is set to be proportional to the square root of the absolute temperature.
● The position of the piston moves up and down due to the force from molecular collisions and gravity. It reaches an equilibrium state when these forces are balanced, resulting in a nearly constant volume.
● The "T" (red) slider allows you to change the absolute temperature. The initial value is 100, and it can be adjusted within the range of 0 to 300. The symbol "t" represents the Celsius temperature.
● The "p" (green) slider adjusts the weight of the piston, allowing you to increase or decrease the pressure. The initial value is 100, and it can be changed within the range of 0 to 200.
● The "N" (blue) slider changes the number of gas molecules inside the cylinder. The initial value is 100, and it can be varied from 0 to 200.
● The value of "V" represents the volume of the gas. Due to the randomness of molecular collisions, this value fluctuates, so it is displayed as a time-averaged value.
● In the ideal gas law pV=NkT (or pV=nRT), the model is set up so that the Boltzmann constant k≈1. Through observing how the volume is determined by numerous molecular collisions, you can see why the ideal gas law, as well as Boyle’s and Charles’s laws, hold true.

Back to Contents Page