# A solution of barium hydroxide, Ba(OH)_2 contains 4.285 grams of barium hydroxide in 100 mL of solution. What is the molarity of the solution?

May 9, 2018

We know the molar mass of barium hydroxide is 171.34 (you can google this or just add the mass of each atom in the molecule). Knowing that $m o l a r i t y = \frac{m o l s}{l i t e r s}$ we need to turn that 4.285 g Ba(OH)2 into mols.
Plugging this all back into the equation for molarity we get $m o l a r i t y = \frac{0.2500 m o l}{0.100 L}$ giving us a molarity of 2.5 M