posted by evelyn .
A solution contains 5.00% (by mass)NaCl. The density of the solution is 1.064 g/cm^3. What is the molarity of NaCl?
5.00% w/w NaCl means 5.00 g NaCl per 100 g solution.
mols NaCl = grams/molar mass. Solve for mols NaCl.
mass soln = volume x density. Solve for volume and convert to L.
Finally, M = mols/L soln.