Question

What is the mass of NaCl required to make 140 grams of a 12% solution of NaCl in water?

Answer 1

Answer:

mass of NaCl required = 17 grams

Explanation:

Mass% = mass of solute X 100 / total mass of solution

mass%= mass of solute X 100 / mass of solute + mass of solvent

given:

Mass of solution = 140 grams

mass % = 12%

Putting values

12 = mass of NaCl X 100 / 140

mass of NaCl = 12 X 140 /100 = 16.8 grams

mass of NaCl required = 17 grams

Answer 2

Answer:

C. 17 grams.

Explanation:

∵ mass % = [mass of solute/mass of solution] x 100.

mass of solute (NaCl) = ??? g & mass of solution = 140.0 g.

∴ mass of NaCl = (mass %)(mass of solution)/100 = (12.0)(140.0)/100 = 16.80 g ≅ 17.0 g.