Temperature required for new rms speed

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Homework Help Overview

The discussion revolves around determining the temperature required for helium gas molecules to achieve a specified root mean square (rms) speed of 733 m/s. The relevant equation involves the rms speed, Boltzmann's constant, and the mass of the gas molecules.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants discuss the application of the rms speed equation and question the correct mass to use for helium gas molecules. There is also mention of an alternative approach using the ideal gas law, raising questions about the missing quantity of material.

Discussion Status

Participants are actively engaging with the problem, offering different perspectives on the mass of helium and the implications of the ideal gas law. There is no explicit consensus on the approach, but guidance has been provided regarding the mass to use.

Contextual Notes

Some participants note the absence of certain information, such as the quantity of material (n), which complicates the application of the ideal gas law. There is also a discussion about the mass of helium and its atomic structure.

rubenhero
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Homework Statement


c) Find T, the temperature at which He gas molecules have an rms speed of v = 733 m/s.


Homework Equations


Vrms = √(3kT/m)


The Attempt at a Solution


(Vrms2m)/3k = T
(7332*.004kg)/(3*1.381e-23J/k) = T
5.187e25k = T

Any help with figuring out what I did wrong is appreciated!
 
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Is not 'm' the mass of one MOELECULE of hydrogen?
 
You could use the following to solve if you are given the quantity of material (n):

P*V=n*R*T <=> T=(P*V)/(n*R)

For R is a constant: R=8.31
 
Thank you grzz and mtayab1994 for responding. It would be easier if the problem did provide n to use PV = nRT. I am confused, should I be using .008 kg for the mass because helium gas has 2 atoms?
 
rubenhero said:
Thank you grzz and mtayab1994 for responding. It would be easier if the problem did provide n to use PV = nRT. I am confused, should I be using .008 kg for the mass because helium gas has 2 atoms?

no you are fine with using .004kg
 
Last edited:
By the way you can use the following as well
ee2357aaf50f4db86dac6622e7f8cc02.png
 

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