Question #5f7d6

1 Answer
Stefan V.
Apr 11, 2017

"189 mL"

Explanation:

The solution's volume by volume percent concentration, "v/v %", tells you the number of milliliters of solute present for very "100 mL" of solution.

Your target solution must be "25% v/v" formic acid, which means that it must contain "25.0 mL" of formic acid, the solute, for every "100 mL" of solution.

You can use the solution's percent concentration as a conversion factor to calculate the volume of formic acid that must be present in "755 mL" of solution in order to have a "25% v/v" solution.

755 color(red)(cancel(color(black)("mL solution"))) * overbrace("25.0 mL formic acid"/(100color(red)(cancel(color(black)("mL solution")))))^(color(blue)("= 25.0% v/v")) = color(darkgreen)(ul(color(black)("189 mL formic acid")))

The answer is rounded to three sig figs.

You can thus say that adding "189 mL" of formic acid to enough water to make the final volume of the solution equal to "755 mL" will give you a "25.0% v/v" formic acid solution.

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