How would you make up 100 mL of a 0.10 M NaCl solution?

There are a number of ways to express concentration of a solution. This includes molarity. Molarity is expressed as the number of moles of solute per volume of the solution.

0.10 M = 0.10 mol NaCl / L solution (0.1 L) = 0.01 mol NaCl (58.44 g / mol) = 0.5844 g NaCl needed

Therefore, to prepare the solution, you need to dissolve 0.5844 g of NaCl to 100mL water.

0.01 moles NaCl into 0.1 Liter solution