# Question #b81e1

##### 1 Answer

You use the density and percent concentration by mass of the stock solution.

#### Explanation:

You know that you're dealing with a *nitric acid*,

To get the solution's percent concentration by volume, you would need to have some information about the *stock solution* of nitric acid used to make the

The idea here is that your *volume of the stock solution* used to prepare the

Usually, nitric acid stock solutions have a percent concentration by mass of nitric acid equal to

Use nitric acid's molar mass to determine how many grams of acid you get in your

#1color(red)(cancel(color(black)("mole HNO"""_3))) * "63.013 g"/(1color(red)(cancel(color(black)("mole HNO"""_3)))) = "63.013 g"#

Now focus on finding what volume of the stock solution will contain **63.013 g** of nitric acid.

To make calculations easier, assume that you have a

#1color(red)(cancel(color(black)("L"))) * (1000color(red)(cancel(color(black)("mL"))))/(1color(red)(cancel(color(black)("L")))) * "1.41 g"/(1color(red)(cancel(color(black)("mL")))) = "1410 g"#

Since nitric acid makes up **70.2%** of this mass, you know that the

#1410color(red)(cancel(color(black)("g solution"))) * ("70.2 g HNO"""_3)/(100color(red)(cancel(color(black)("g solution")))) = "989.82 g HNO"""_3#

Now, the volume of this solution that will contain **63.013 g** of nitric acid is

#63.013color(red)(cancel(color(black)("g HNO"""_3))) * "1000 mL stock"/(989.92color(red)(cancel(color(black)("g HNO"""_3)))) = "63.7 mL"#

So, you prepared your **enough water** to make the total volume of th solution equal to

This means that the volume by volume,

#"%v/v" = V_(HNO_3)/V_"sol" xx 100#

#"%v/v" = (63.7color(red)(cancel(color(black)("mL"))))/(1000color(red)(cancel(color(black)("mL")))) xx 100 = 6.37 = color(green)("6.4% v/v")#

**SIDE NOTE** *The answer will depend on the percent concentration by mass, and implicitly on the density, of the stock solution of nitric acid.*