# How many grams of #KNO_3# should be used to prepare 2.00 L of a 0.500 M solution?

##### 1 Answer

#### Explanation:

**Molarity** is simply a measure of how many **moles of solute** you get **per liter** of solution.

#color(blue)(|bar(ul(color(white)(a/a)"molarity" = "moles of solute"/"one liter of solution"color(white)(a/a)|)))#

This means that in order to find a solution's molarity, you need to know two things

how manymoles of soluteit containsits volumeexpressed in liters

Now, you already know the *molarity* and *volume* of your target solution, which means that you can use the definition of molarity to find how many moles of potassium nitrate,

Molarity is measued in *moles per liter*, *molar*, **for every**

Well, if you get *for very* liter of solution, and your solution has a total volume of

#2 xx "0.500 moles" = "1.00 moles KNO"_3#

So, what mass of potassium nitrate is equivalent to **one mole** of the compound?

Potassium nitrate's **molar mass**, **one mole** of potassium nitrate. In this case, the answer must be rounded to three **sig figs**, so

#m_(KNO_3) = color(green)(|bar(ul(color(white)(a/a)"101 g KNO"_3color(white)(a/a)|)))#