Question

Calculate the mass/mass percent of a saturated solution of NaCl. Use the data from Table 9.2.1 "Solubilities of Various Solutes in Water at 25°C (Except as Noted)", assume that masses of the solute and the solvent are additive, and use the density of H2O (1.00 g/mL) as a conversion factor.

Table 9.2.1 below

NaCl(s)

36.0

Answer 1

Given conversion factor of NaCl_(s) (solute)= 36.0 (this means that 36 g of NaCl dissolve in 100 mL of water.)

Density of water = 1.00 g/mL

So mass of 100 mL water = volume x density = 100 mL x 1.00 g /mL = 100g

Mass of 100 mL water = 100g (solvent)

Now

mass percent = (grams of solute / grams of solute plus solvent) x 100

mass percent = (36.0 g / 100 g ) x 100

mass percent of NaCl = 36.0 %

mass percent of NaCl = 36.0 %