Question #5f7d6

1 Answer
Apr 11, 2017

Answer:

#"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.