In: Chemistry
2.65 g of Ba(OH)2 is dissolved in 70.0 mL of water to produce a saturated solution at 200C. Calculate the solubility in units of g/100 mL; g/L ; and M.
Molar mass of Ba(OH)2 = [1*137.327 + 2*(15.9994 + 1.008)] g/mol = 171.3418 g/mol.
Moles of Ba(OH)2 = (2.65 g)/(171.3418 g/mol) = 0.01547 mole.
Volume of water taken = 70.0 mL = (70.0 mL)*(1 L/1000 mL) = 0.07 L.
70.0 mL water contains 2.65 g Ba(OH)2.
Therefore, 100.0 mL water contains (2.65 g)*(100 mL/70 mL) = 3.7857 g ≈ 3.786 g.
Solubility of Ba(OH)2 = 3.786 g/100 mL (ans).
Again 100 mL water = (100 mL)*(1 L/1000 mL) = 0.100 L.
Solubility of Ba(OH)2 in a liter of water = (3.786 g/100 mL) = (3.786 g/0.100 L) = 37.86 g/L (ans).
Solubility of Ba(OH)2 in M = (0.01547 mole)/[(70.0 mL)*(1 L/1000 mL)] = (0.01547 mole)/(0.07 L) = 0.221 mol/L = 0.221 M (ans).