# If 42.9mL rubbing alcohol is dissolved of in water to make 215mL of solution, what is the concentration expressed in volume/volume % of the solute?

##### 1 Answer

#### Explanation:

A solution's *volume by volume percent concentration*, **volume of solute** present in **of solution**.

#color(blue)(|bar(ul(color(white)(a/a)"% v/v" = "volume of solute"/"100 mL of solution" xx 100color(white)(a/a)|)))#

This means that all you have to do in order to find a solution's

In your case, you know that you're adding

Since you know how many milliliters of solute you have in **conversion factor** to see how many milliliters of solute would correspond to

#100 color(red)(cancel(color(black)("mL solution"))) * "42.9 mL solute"/(215color(red)(cancel(color(black)("mL solution")))) = "20.0 mL solute"#

So, if

#"% v/v" = "20.0 mL solute"/(color(red)(cancel(color(black)(100)))"mL solution") * color(red)(cancel(color(black)(100))) = color(green)(|bar(ul(color(white)(a/a)color(black)("20.0 %")color(white)(a/a)|)))#

The answer is rounded to three **sig figs**.