Question

Suppose the Solubility of NaCl in water at 20. C is 36.00 g. Given the density of water is 0.9987 g/mL and the density of the solution is 1.105 g/mL.

A: Find % by mass of NaCl

B: Find the molarity of the solution.

Answer 1

A)

9.62%

Explanation

mass of 1ml NaCl solution = 1.105g

mass of water = 0.9987g

mass of NaCl =(1.105g - 0.9987g) = 0.1063g

percent by mass of NaCl =( 0.1063g/1.105g )×100 = 9.62%

B)

1.819M

Explanation

mass of NaCl in 1ml of NaCl solution = 0.1063g

molar mass of NaCl = 58.44g/mol

Number of moles of NaCl = 0.1063g/58.44g/mol = 0.00181896mol

Molarity = Number of moles per liter of solution

Therefore

Molarity of the solution = (0.00181896mol/1ml)×1000ml = 1.819M