Calculate Number of Solute Molecules in 30mM Solution in 100nm Sphere

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Discussion Overview

The discussion revolves around calculating the number of solute molecules in a 30mM solution contained within a spherical volume of 100nm radius. Participants are exploring the application of concentration formulas to derive the number of molecules present.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested, Mathematical reasoning

Main Points Raised

  • Alfio initially calculates approximately 6400 solute molecules based on the concentration and volume but expresses uncertainty about the correctness of his conversion.
  • Another participant questions the clarity of the dimensions provided, specifically whether 100nm refers to radius or diameter.
  • Alfio clarifies that 100nm is the radius and states that he derives N = 6400 using the formula c = N/(N_A*V), where c is the concentration.
  • A participant acknowledges that the formula is correct but mentions obtaining a different number without asserting correctness.
  • Alfio revisits his calculation and reports a new estimate of around 75000 molecules, indicating uncertainty in his results.
  • Another participant confirms that they also arrived at a similar number of molecules as Alfio's revised calculation.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the correct number of solute molecules, with multiple competing estimates presented and uncertainty expressed regarding the calculations.

Contextual Notes

Participants have not fully resolved the assumptions related to the volume calculation or the definitions used in the concentration formula, which may affect the results.

towerette
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Suppose i have a spherical volume of 100nm with a solution 30mM.
How many solute molecules it corresponds to?

My answer is about 6400...is that correct?
im just not sure i did some conversion correctly...

Thanks
Alfio
 
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100nm is what? Radius? Diameter?

6400 of what?

--
 
Sorry for not being clear, 100nm is the radius.
N = 6400 is the number of solute particles I get
from the formula c = N/(N_A*V), just wanted to know
if its right.
c = 30mM

Thanks.
Alfio
 
Formula is OK, but I got different number. Not necesarilly correctly.

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methods
 
I did the calculation again, i got around 75000 molecules, right?
Well..it seems I'm playing dices...


Alfio
 
That's what I got as well.

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