A 0.7011-g mixture of sodium chloride and sodium nitrate is completely dissolved in water. When silver nitrate is added to the solution, 0.9805 g of solid precipitate. What is the percent by mass of chloride in the initial mixture?

34.59 %

Explanation:

Sodium chloride dissolves in water as follows:

NaCl (s) → Na⁺ (aq) + Cl⁻ (aq)

Chloride ions are then precipitated with silver ions:

Ag⁺ (aq) + Cl⁻ (aq) → AgCl (s)

Now we use the give mass of AgCl to calculate the moles of Cl:

0.9805 g AgCl : 143.32 g/mol = 6.841x10⁻³ mol AgCl

mol AgCl = mol Cl

6.841x10⁻³ mol Cl * 35.45 g/mol = 0.2425 g Cl

Finally we calculate the mass percent of Cl in the initial mixture:

0.2425g / 0.7011g * 100% = 34.59 %