Question

Question #c5ab5

Answer 1

It is not a dilution, but a concentration increase by a factor of 10

Explanation:

If we go for the definition of dilution factor, you would find that it refers to the final volume/aliquot volume (final volume = aliquot + diluent) [DILUTIONS: Principles and Applications, David B. Fankhauser, http://biology.clc.uc.edu/fankhauser/labs/microbiology/dilutions.htm],

In this case the question would be what is the final concentration of my solution? And if it is smaller than the initial one, yes you have a dilution, but as it seems to be in reality you are increasing the concentration of your solution.

• Lets see then the starting conc. is 5g`//`20ml = 0.25g`//`ml `=` 250mg`//`mL `=` 0.25mg`//` `mu`L

• when you take 3ml and then evaporating the solvent, you are ending with:
  250mg/mL`xx` 3mL `=` 750mg of the solute.

• dissolving them in 300`mu`l yield the following solution
  750mg`//`300`mu`L `=` 2.5mg`//` `mu`L

• Now your starting concentration was 0.25mg`//` `mu`L and your actual one is 2.5mg`//` `mu`L then your concentration was increased by a factor of 10.

-Need to be careful with units, if you want to present them back in g`//`mL, nothing else have to be done. Because you should multiply and divide by 1000, leaving the amount unaffected.
2.5mg`//` `mu`L `=` 2.5g`//`mL