What is the molarity (moles per liter) of an aqueous solution that is prepared by dissolving 5.58g NaOH (MW=40) in enough water to make 250mL of solution?

Answer 1

How many mols NaOH do you have? That's mols = grams/molar mass.
Then M = mols/L solution.

Answer 2

Thank you..

I get

5.58g NaOH / 40g NaOH / 0.25L = 0.558 NaOH solution