Question #14940

1 Answer
Aug 11, 2016

Answer:

#10.3%#

Explanation:

A solution's volume by volume percent concentration, #"% v/v"#, tells you the volume of solute present in #"100 mL"# of solution.

This means that in order to find a solution's volume by volume percent concentration you must know

  • the volume of solute dissolved in your sample
  • the total volume of the solution

In your case, you know that #"16.0 mL"# of acetone, your solute, is dissolved in enough solvent to make the total volume of the solution equal to #"155 mL"#. This is the known composition of the solution.

Since your goal here is to figure out how many milliliters of acetone are present in #"100 mL"# of solution, use the known composition of the solution as a conversion factor to say

#100 color(red)(cancel(color(black)("mL solution"))) * overbrace("16.0 mL acetone"/(155 color(red)(cancel(color(black)("mL solution")))))^(color(blue)("known composition")) = "10.3 mL acetone"#

So, you know that #"100 mL"# of solution contain #"10.3 mL"# of acetone, which means that the solution's volume by volume percent concentration will be

#color(green)(|bar(ul(color(white)(a/a)color(black)("% v/v" = 10.3%)color(white)(a/a)|)))#

The answer is rounded to three sig figs.