posted by kim on .
Describe how you would prepare 250.0 mL of a 0.500 M solution of NaCl by using apparatus found in a chemistry lab.
Use a 250 mL volumetric flask. You want 58.5 (that's approximate for NaCl but you need to do it exactly) in a liter for 1 M, or 1/2 that for 0.5 M. Then for only 250 mL you need 1/4 of that (which works out to be 58.5/8 but check me out on that). Dissolve in a small amount of water in the flask, then make to the mark with distilled or deionized water. (The important point to make with this type problem is for you to recognize that you don't take 58.5/8 g NaCl and ADD IT TO 250 mL because that leads to a volume greater than 250 mL. That's why you dissolve it in a little water in the flask, then make the total solution up to the mark on the neck of the flask.