Question

Question #e0ae8

Answer 1

`20. "mL"` should be correct.

Explanation:

This a dilution problem, so we can use the formula

`M_ "conc"V_ "conc" = M_ "dil"V_ "dil"`

where

• `M_"conc"` is the molar concentration (molarity) of the concentrated, stock solution, and `M_"dil"` is the molar concentration of the dilute solution

• `V_"conc"` is the volume of the concentrated, stock solution, and `V_"dil"` is the volume of the dilute solution

Let's rearrange the equation to solve for the volume of the stock solution, `V_"conc"`, and plug in our known values:

`V_ "conc" = (M_ "dil"V_ "dil")/(M_ "conc") = ((0.50cancel(M))(100.0"mL"))/(2.5cancel(M)) = color(red)(20."mL"`

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