(simple?) question on number of molecules in an area

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SUMMARY

The discussion centers on the calculation of the number of molecules in a given volume using particle density. The participant clarifies that the symbol ##\rho## represents particle density, defined as the number of particles per cubic meter (number of particles/m³), rather than mass density (kg/m³). By integrating the volume and multiplying it by the particle density, one can accurately determine the total number of molecules present in that volume. This distinction is crucial for correctly interpreting the relationship between density and the number of particles.

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  • Understanding of particle density and its units (number of particles/m³).
  • Basic knowledge of integration in calculus.
  • Familiarity with the concept of volume in three-dimensional space.
  • Knowledge of the relationship between mass and particle count in physical chemistry.
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  • Research the concept of particle density and its applications in physical chemistry.
  • Study integration techniques relevant to calculating volumes in physics.
  • Explore the relationship between mass density and particle density in various materials.
  • Learn about Avogadro's number and its significance in determining the number of molecules in a sample.
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Students in chemistry or physics, educators teaching particle dynamics, and anyone interested in understanding molecular calculations in various scientific contexts.

rwooduk
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Homework Statement


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Homework Equations


Please see below.

The Attempt at a Solution



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I'm probably being really stupid here but how can the number of molecules equal

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If we integrate we get a volume multiplied by density, how can that equal a number of particles?
 
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##\rho## is not a mass density (kg/m3) but a particle density (number of particles/m3).
 
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BvU said:
##\rho## is not a mass density (kg/m3) but a particle density (number of particles/m3).

Of course! many thanks for clearing this up.
 

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