Solid sodium chloride is dissolved completely to prepare 250.0 mL of an aqueous solution
CHEMISTRY · Multi-part · AP · Chemistry · Atomic Structure and Properties · Atomic Structure and Properties
Problem
Solid sodium chloride is dissolved completely to prepare 250.0 mL of an aqueous solution. The mass of NaCl used is 7.30 g (molar mass = 58.44 g mol⁻¹). After the solution is prepared, additional distilled water is added until the total volume reaches 400.0 mL.
Answer the following questions.
(a) Calculate the initial molarity of the sodium chloride solution before any additional water is added.
(b) Determine the new molarity of the solution after the volume is increased to 400.0 mL.
(c) Explain why the concentration changes even though the amount (in moles) of NaCl remains the same.