Does Halving Molecules Double RMS Speed?

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SUMMARY

The discussion centers on the relationship between the number of gas molecules and the root mean square (RMS) speed in an isothermal process. It is established that while the average kinetic energy remains constant at a given temperature, halving the mass of the molecules results in a doubling of the RMS speed, as indicated by the equation m1(v1)² = m2(v2)². Specifically, if m2 equals m1/2, then v2² equals 2v1², confirming the direct correlation between mass and speed in gas behavior.

PREREQUISITES
  • Understanding of the ideal gas law (pV = NkT)
  • Familiarity with kinetic molecular theory
  • Basic knowledge of root mean square speed calculations
  • Concept of isothermal processes in thermodynamics
NEXT STEPS
  • Study the derivation of the ideal gas law and its implications
  • Explore kinetic molecular theory in greater depth
  • Learn about the mathematical formulation of RMS speed in gases
  • Investigate the effects of temperature on gas behavior
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Students of physics, chemists, and anyone interested in thermodynamics and gas behavior, particularly those studying the properties of gases under varying conditions.

sArGe99
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Does the rms speed of a gas change when the no of molecules are lowered, isothermally?
I know that at same temp, avg kinetic energy remains the same.
m1 (v1)2 = m2 (v2)2

If m2 = m1/2, v22 = 2 v12
Is this correct?
 
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The number of molecules is N as in pV = NkT. The symbol m stands for the mass of a molecule, not the number of molecules.
 

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