If 0.35 moles of NaCl was dissolved in enough water to make 200 ml of solution, what is the molarity? (NOTE: 1000 mL = 1 L)

Question

For full credit you must list your givens, show the formula, all your work, and box/highlight your answer with correct units & significant figures!

Answer 1

We first need to know that molarity is calculated by dividing the number of moles of solute by the volume of solution in liters. We are given that there are 0.35 mol NaCl, and we can use the conversion 1000 mL = 1 L to convert 200 mL of solution to 0.200 L solution.

Then we can calculate molarity from (0.35 mol)/(0.200 L) = 1.75 M NaCl. However, we must realize that there should only be 2 significant figures because 0.35 is only 2 significant figures. Therefore, our solution must be 1.8 M NaCl.