Larissa needs to make 500ml of 2.00 M NaCl. The molecular weight of NaCl is 58.44. How does she make 500ml of 2.00 M NaCl? Question 3 options: A) Measure 29.22g NaCl and dissolve it into 500ml water. B) Measure 29.22g NaCl, dissolve it into 400ml water, and then top off to 500ml in a volumetric flask. C) Measure 58.44g NaCl and dissolve it into 500ml of water. D) Measure 58.44g NaCl, dissolve it into 400ml water, and then top off to 500ml in a volumetric flask.

D) Measure 58.44g NaCl, dissolve it into 400ml water, and then top off to 500ml in a volumetric flask.

Explanation:

2.00M NaCl is a solution that contains 2.00 moles of NaCl per liter of solution.

As you want to prepare 500mL = 0.500L of the solution you need:

0.500L * (2.00 moles / L) = 1.00 moles of NaCl are required to prepare the solution.

Now, to convert these moles to grams you must use Molar weight (58.44g/mol) as follows:

1 moles of NaCl * (58.44g / mol) = 58.44g of NaCl are required to dissolve in 500mL to prepare the 2.00M solution.

And right option is:

-You can't top off a solution before dissolve all solute because it is possible the volume changes-