Answer to Question #138246 in General Chemistry for akshay wadhwa

Question

A stock solution of copper, 1000.0 (± 0.3) mg Cu /L, is diluted tenfold by diluting 10.00 (± 0.04) mL stock to a final volume of 100.00 (± 0.05) mL. The concentration of the diluted solution, calculated using the formula Cstock.Vstock = Cdiluted.Vdiluted, is of course 100 mg Cu /L.

Cdiluted = 1000.0(±0.3) x 10.00(±0.04) / 100.00(±0.05)

Calculate the % relative uncertainty in the concentration of the 100 mg/L diluted solution. The numbers in parenthesis are absolute uncertainties. Enter your answer to two significant figures in the format 0.0E0. Do NOT include the % sign.

Answer 1

The idea here is that in a 10-fold dilution, the volume of the diluted solution is 10 times higher than the volume of the stock solution.

This is equivalent to saying that the concentration of the stock solution is 10 times lower than the concentration of the diluted solution.

In other words, you're performing a 1:10 dilution, i.e. you're diluting the stock solution by a factor fo 10.

DF= Vdiluted/Vstock → the dilution factor

So depending on the nature of the substance that you're diluting, you can add enough water to the stock solution to get the total volume. 

% relative uncertainty in the concentration of the 100 mg/L diluted solution = 0.24