# Question #eb6dd

##### 1 Answer

#### Explanation:

*Rubbing alcohol* is simply a solution of isopropyl alcohol of various *concentrations by volume*.

The *volume by volume percent concentration*, *milliliters* of solute, which in this case is isopropyl alcohol, you get per

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

In your case, the solution has a concentration of **pure** isopropyl alcohol **for every**

You can thus use the volume by volume percent concentration as a **conversion factor** to calculate how many milliliters of isopropyl alcohol you have in your

#420 color(red)(cancel(color(black)("mL rubbing alcohol"))) * overbrace("70 mL isopropyl alcohol"/(100color(red)(cancel(color(black)("mL rubbing alcohol")))))^(color(blue)("= 70% v/v")) = color(green)(|bar(ul(color(white)(a/a)color(black)("290 mL isopropyl alcohol")color(white)(a/a)|)))#

I'll leave the answer rounded two two **sig figs**.

You can use the same technique to figure out how many milliliters of isopropyl alcohol you have in