# What is Kinetic theory gases: Definition and 12 Discussions

The kinetic theory of gases is a simple, historically significant classical model of the thermodynamic behavior of gases, with which many principal concepts of thermodynamics were established. The model describes a gas as a large number of identical submicroscopic particles (atoms or molecules), all of which are in constant, rapid, random motion. Their size is assumed to be much smaller than the average distance between the particles. The particles undergo random elastic collisions between themselves and with the enclosing walls of the container. The basic version of the model describes the ideal gas, and considers no other interactions between the particles.
The kinetic theory of gases explains the macroscopic properties of gases, such as volume, pressure, and temperature, as well as transport properties such as viscosity, thermal conductivity and mass diffusivity. The model also accounts for related phenomena, such as Brownian motion.

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1. ### Equating two formulas for root-mean-square velocity

(a) My question : Are all the formulas correct? If so I can write ##v_{rms}## in form (2) and compare that result with the other velocities to get the answer (rms > average > most probable)
2. ### How Does Doubling the Temperature Affect the Mean Free Path in a Gas?

Say Temperature of a gas doubles, I do not understand how the average distance between particles (mean free path) is unaffected if they are traveling √2 times as fast in a fixed volume V. Root 2 as a factor of increase because T*2 --> KE*2 --> V*2 --> Vrms*√2 Is it because relative to one...
3. ### Pressure exerted by a gas (derivation using the kinetic theory of gases)

In the derivation of finding pressure exerted by a gas using kinetic theory of gases I am not understanding why the time between two collisions is taken as the time for rate of change of momentum when a particle bounces back from the wall. please help me
4. ### Effusing gas onto the interior of an evacuated sphere

Homework Statement A gas effuses into a vacuum though a small hole of area A. Show that if the particles effused into an evacuated sphere and the particles condensed where they collided that there would be a uniform coating. (7.6 of Blundell and Blundell) Homework Equations Angular...
5. ### Pressure should decrease in zero gravity?

Pressure can exist in a container of gas even if there is no gravity. From kinetic theory of gases it is assumed that pressure exists due to momentum transfer between molecules and the wall. Suppose I have a closed container on Earth at sea level filled with air. Now I carried it to zero gravity...
6. ### How to Calculate Work Done by a Gas in Thermodynamics?

Homework Statement Please see the attached image Homework Equations pv=nRTThe Attempt at a Solution i don't know how to calculate the work done by the gas in the question and i calculated the change in internal energy.
7. ### Mean free path and speed as a function of pressure and temp

Homework Statement I know that at 18,000 ft. above mean sea level, the atm. pressure ~half of what it is at seal level (760 Torr). The temperature also decreases by 70C. a. How would this change the speed distribution of the air molecules quanitatively? b.How would it change the mean free...
8. ### Relationship between pressure and thermal conductivity

Homework Statement I would like to derive an equation that relates the thermal conductivity to the pressure using the kinetic theory of gases. However, I assumed that thermal conductivity was independent of pressure. Homework Equations I know that P = 2N/3V (1/2mv^2) Also: I believe that...
9. ### What is the molecular diameter of hydrogen using Van der Waals coefficients?

Homework Statement Calculate the molecular diameter of hydrogen, assuming the spherical shape on the basis of van der Waals coefficients. Van der Waals Coefficients for hydrogen a = 0.244 atm L2.mol-2 b*103 = 26.6 L.mol-1 Homework...
10. ### Finding average angle in kinetic theory of gases

Homework Statement "Show that particles hitting a plane boundary have traveled a distance 2λ/3 perpendicular to the plane since their last collision, on average."Homework Equations (Root mean path squared) <x> = 2^(.5)λ λ = ( 2^(.5) * n * sigma )^(-1) ANSWER: The Attempt at a Solution...
11. ### Knudson Effusion between two gasses

Homework Statement Consider two chambers of equal volume separated by an insulating wall and containing an ideal gas, maintained at temperatures T1 = 225K and T2 = 400K. Initially the two chambers are connected by a long tube whose diameter is much larger than the mean free path in either...