Ratio of atomic masses of two ideal gases

In summary: M##, is the equation that proves that?In summary, the conversation discussed the solution to a problem involving the ratio of atomic mass and molar mass. Part (a) stated that ##n_A = n_B## and part (b) found the ratio of atomic mass to be ##M_A = 10M_B##. The definition of Avogadro's number, which is the number of molecules per mole, was also discussed. There was a spelling error in part (b) and the correct wording should be "ratio" instead of "ration". The conversation also mentioned the use of dimensional analysis to find the correct units for a mass of one atom, and the equation ##u ∝ M##
  • #1
ChiralSuperfields
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Homework Statement
Please see below
Relevant Equations
Please see below
For part(b)
1680232199273.png

The solution is, ##1:10##, however, is the wording correct? I don't see how to find the ratio of atomic mass, however, I can solve for the ratio of the molar mass.

##n_A = n_B## from part(a) by setting the internal energy equation for each ideal gas equal
##\frac{M_A}{m_A} = \frac{M_B}{m_B}##
##1000M_A = 10000M_B##
##M_A = 10M_B##

Is the reason they said that is because ##u ∝ M##. Is there a equation that proves that?

Many thanks!
 
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  • #2
What is the definition of Avagadro's number?
 
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  • #3
hutchphd said:
What is the definition of Avagadro's number?
Thank you for your reply @hutchphd!

It is the number of molecules per 1 mol. So has units ##\frac{1}{mol}##

Many thanks!
 
  • #4
I think there is also a spelling error in part(b) it should be ratio not ration
 
  • #5
hutchphd said:
What is the definition of Avagadro's number?
Do you please know whether my answer was correct @hutchphd ?

Many thanks!
 
Last edited:
  • #6
It might be better to write it as ##\frac {number~ of~ molecules}{mole}## in this circumstance
 
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  • #7
hutchphd said:
It might be better to write it as ##\frac {number~ of~ molecules}{mole}## in this circumstance
Thank you for your reply @hutchphd! I agree that is a much better way to write it. However, is the wording to this problem in post #1 wrong? Or dose Avagadro's number relate to this in some way.

Many thanks!
 
  • #8
I found from dimensional analysis that the I can get correct units for a mass of one atom (atomic mass):## \frac{M_A}{N_A} = 10\frac{M_B}{N_A} ##
## u_A = 10u_B##
 

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