Answer to Question #131218 in Molecular Physics | Thermodynamics for Alex

Question

explain in terms of molecules ,how the are inside the cylinder exerts a pressure

Answer 1

Let us consider the gas that does not have any systematic motion. In such a case the individual molecules move randomly in every direction. The molecules collide with the walls of the cylinder, and due to the random motions the pressure force acts perpendicular to the walls of the cylinder. The pressure is equal to the sum of momenta given to the wall with unit area by particles in a unit of time. Moreover, if the gas is in equilibrium, the pressure will be the same in every small volume in our cylinder.

According to the ideal gas law, the pressure is proportional to nT/V, or

$pV = n R T$ , where V is the volume of gas, T is its temperature, n is the amount of substance of the gas (in moles) number density and R is the the gas constant