AP Chemistry Exam Prep

Answer: .50 M

Molarity indicates the number of moles of solute divided by the number of liters of solvent in a solution. Begin this problem by determining the number of moles of NaOH present. 2.0 M = (moles of solute)/.250 L. Solving this expression gives .50 moles NaOH. To find the final molarity, divide the number of moles of NaOH present by the new volume of solvent, 1.0 liter. This simple calculation indicates that the final concentration of the solution is .50 M.