What is the average speed of gas molecules in a given volume and pressure?

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SUMMARY

The average speed of helium (He) gas molecules can be calculated using the root mean square speed formula, Vrms = √(3RT/M). In this case, R is the ideal gas constant (8.31 J/mol·K), T is the temperature (241 K), and M is the molar mass of helium, which is derived from the mass of a single helium atom (6.65e-27 kg). The correct molar mass for helium is 4.00 g/mol (or 4.00e-3 kg/mol), leading to an average speed calculation that provides definitive insights into molecular motion under specified conditions.

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Homework Statement


The mass of a single HE atom is 6.65e-27kg. You have 5.00e-6 mole of HE gas which is occupying a volume of 1.00e-4m^3. when at pressure of 100Pa. Determine the temp of gas AND the average speed of the gas molecules.

**I've found the temp of gas i need help on the avg speed - i believe I'm close

Homework Equations


Vrms=\sqrt{3(R)(T)/(M)}


The Attempt at a Solution


Vrms=\sqrt{3(8.31J/mol K)(241)/(6.65e-27kg?)}

i'm not certain if i use 6.65e-27kg as molar mass?
 
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hatcheezy said:

Homework Statement


The mass of a single HE atom is 6.65e-27kg.
Note it gives you the mass of a single atom

hatcheezy said:
You have 5.00e-6 mole of HE gas
This is the amount of moles present

hatcheezy said:
i'm not certain if i use 6.65e-27kg as molar mass?
After reading the above do you still think this?
 
ahh i do apologise i had not realized you have calculated the temperature, please ignore the post above
 

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