Mass/Mass problem help?

Question

If 10.0 ml 20.0% mass/mass solution of NaCl (density of solution = 1.09 g /ml) is placed into a volumetric flask and diluted with water to a volume of 250.0 ml of solution. What is the molarity of the resulting solution?

solution and explanation would be nice. thanks!

Answer 1

10.0mL NaCl solution x 1.09g/ 1 mL= 10.90 g

*using density you can find the amount of grams of NaCl per mL of solution

10.90 g NaCl x 1 mol/58.443g NaCl= .187 moles

*Using the molar mass and the amount of grams present, you find moles

M=mol/L

.187 moles NaCl/ .250 L = .748 M

*Use the definition of Molarity to find it!!

Goodluck!!