A 20.0 mL sample of NaCl solution has a mass of 21.040 g. After the solution is

Question

A 20.0 mL sample of NaCl solution has a mass of 21.040 g. After the solution is evaporated to dryness, the dry salt residue has a mass of 4.348 g. Calculate the following concentrations for the NaCl solution. A) Mass/Mass% B)Mass/Volume% C)Molarity(M) A 20.0 mL sample of NaCl solution has a mass of 21.040 g. After the solution is evaporated to dryness, the dry salt residue has a mass of 4.348 g. Calculate the following concentrations for the NaCl solution. A) Mass/Mass% B)Mass/Volume% C)Molarity(M) A) Mass/Mass% B)Mass/Volume% C)Molarity(M)

Explanation / Answer

A 20.0 mL sample of NaCl solution has a mass of 21.040 g. After the solution is evaporated to dryness, the dry salt residue has a mass of 4.348 g. Calculate the following concentrations for the NaCl solution.

A) Mass/Mass% = (dry salt mass / original mass ) x 100

                             = (4.348/ 21.040 ) x 100

                            = 20.66

B)Mass/Volume% = (4.348 / 20 ) x 100

                               = 21.74%

C)Molarity(M) = moles of solute in 1 litre solution

moles = mass / molar mass

NaCl molar mass = 58.5

moles = 4.348 / 58.5 = 0.07432

molarity = (0.07432 / volume ) x 1000

              = (0.07432 /20) x1000

              = 3.71 M

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.