Question #14940

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.