What is the molarity (mol/dm3) of a solution prepared by dilution of 0.125 moles of sodium chloride (NaCl) to 2.50x102 mL with water?

To find the molarity (mol/dm³) of a solution, you need to know the number of moles of solute and the volume of the solution.

In this case, you are given that the number of moles of sodium chloride (NaCl) is 0.125 moles, and the volume of the solution is 2.50x10² mL. However, it is more convenient to work with liters rather than milliliters, so you need to convert the volume to liters.

To convert milliliters (mL) to liters (L), you divide the volume by 1000:

2.50x10² mL ÷ 1000 = 0.250 L

Now that you have the volume in liters, you can calculate the molarity using the equation:

Molarity (mol/dm³) = Moles of Solute ÷ Volume of Solution (in liters)

Molarity = 0.125 moles ÷ 0.250 L

Molarity = 0.5 mol/dm³

Therefore, the molarity of the solution prepared by dilution of 0.125 moles of sodium chloride (NaCl) to 2.50x10² mL with water is 0.5 mol/dm³.