Question

What is the molarity of a solution prepared by dissolving 27.2 g of sodium chloride in enough water to prepare 500.0 ml of solution?

Answer 1

Molar mass NaCl : 58.44 g/mol

number of moles:

n = mass solute / molar mass

n =27.2 / 58.44

n = 0.465 moles

Volume in liters : 500.0 mL / 1000 = 0.5 L

therefore:

Molarity = moles solute / volume

Molarity = 0.465 / 0.5 => 0.93 M

Answer 2

Molarity is calculated by dividing the number of moles of solute by the volume (in liters) of the solution.

Moles NaCl, n: n = mass /molar mass = 27.2 g / (58.45 g/mol)
n = 0.465 moles
Molarity of solution:
M = n / V = (0.465 moles) / (0.50 L) = 0.93 M
Thus, the molarity of the solution is approximately 0.93 M.