Question

a mixture contains only sodium chloride and potassium chloride. a .1586-g sample of the mixture was dissolved in water. it took 22.90 mL of 0.1000 M AgNO3 to completely precipitate all the chloride present. what is the composition(by Mass percent) of the mixture?

Answer 1

Two equations and two unknowns. Solve simultaneously.

eqn 1.
g NaCl + g KCl = 0.1586g

eqn 2.
mol AgCl from NaCl + mol AgCl from KCl = mol AgCl total

Now put those into math form.
Let X = g NaCl
and Y = g KCl
MM stands for molar mass.
---------------------
eqn 1.
X + Y = 0.1586 g

eqn 2.
(X/MM NaCl) + (Y/MM KCl) = 0.02290*0.1000

Find X and Y, then
%NaCl = (X/0.1586)*100 = ?
Post your work if you get stuck.
^KCl = (Y/0.1586)*100 = ?

Answer 2

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