How many grams of #KNO_3# should be used to prepare 2.00 L of a 0.500 M 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 many moles of solute it contains
- its volume expressed 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,
Well, if you get
#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,
#m_(KNO_3) = color(green)(|bar(ul(color(white)(a/a)"101 g KNO"_3color(white)(a/a)|)))#