# Question 14940

Aug 11, 2016

10.3%

#### Explanation:

A solution's volume by volume percent concentration, $\text{% v/v}$, tells you the volume of solute present in $\text{100 mL}$ 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 $\text{16.0 mL}$ of acetone, your solute, is dissolved in enough solvent to make the total volume of the solution equal to $\text{155 mL}$. This is the known composition of the solution.

Since your goal here is to figure out how many milliliters of acetone are present in $\text{100 mL}$ 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 $\text{100 mL}$ of solution contain $\text{10.3 mL}$ 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.