Question

Q4) Suppose you prepare 950 mL of a solution by dissolving 100 grams of NaCl in 900 mL of water. Assuming the density of pure water to be 1 g/mL, answer the following questions with regards to this solution:

a) What is the mass percent of water in this solution?
b) What is molarity of NaCl solution?
c) What is the mole fraction of NaCl in the solution?

Answer 1

a. mass % H2O = (grams H2O/grams soln)*100 = (100g H2O/1000g)*100 = ?

b. M = moles NaCl/L soln = moles NaCl/0.950 = ?
moles NaCl = grams NaCl/molar mass

c. mols NaCl you have.
mols H2O = grams H2O/molar mass
total moles = ?

XNaCl = moles NaCl/total moles.