3.90 L of a 4.50 M NaOH solution

Question

Calculate the grams of solute needed to prepare

Answer 1

4.50 M NaOH means there are 4.50 moles of NaOH per liter of total solution volume.

So, if we want to prepare 3.90 L of total solution, how many moles of NaOH do we need?

*** 3.90 L x 4.50 moles/L = 17.55 moles of NaOH needed

Now all we have to do is convert this to mass (grams). To do this, we use the molar mass of NaOH

*** 17.55 moles NaOH x 39.99 g/mol = 701.8 g NaOH = 702 g NaOH needed (to 3 significant figures)