A mixture contains only sodium chloride and potassium chloride. A 0.1586-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?

First, we need to write the chemical reactions between sodium chloride, potassium chloride, and silver nitrate. The reactions are: NaCl(aq) + AgNO3(aq) → AgCl(s) + NaNO3(aq) KCl(aq) + AgNO3(aq) → AgCl(s) + KNO3(aq) Both reactions have a 1:1 mole ratio between the chloride salts (both sodium and potassium) and the silver nitrate.

We are given that it takes 22.90 mL of 0.1000 M AgNO3 solution to react with all the chloride ions present in the sample. First, convert the volume of AgNO3 to liters: 22.90 mL × (1 L / 1000 mL) = 0.0229 L Next, calculate the moles of chloride ions that reacted with AgNO3 using its molarity: moles of Cl- ions = molarity of AgNO3 × volume of AgNO3 in L moles of Cl- ions = 0.1000 mol/L × 0.0229 L moles of Cl- ions = 0.00229 mol

We have the moles of chloride ions. Now we need to find their mass. Mass of Cl- ions = moles of Cl- ions × molar mass of Cl Mass of Cl- ions = 0.00229 mol × 35.45 g/mol Mass of Cl- ions = 0.0811 g

The mass of the total chloride ions contains the sum of the mass of chloride ions from both NaCl and KCl. We have the mass of total chloride ions (0.0811 g) and the mass of the sample (0.1586 g). We can calculate the mass percent of NaCl and KCl in the mixture using the mass of chloride ions. Mass percent of NaCl + KCl = (Mass of Cl- ions / Mass of the sample) × 100% Mass percent of NaCl + KCl = (0.0811 g / 0.1586 g) × 100% Mass percent of NaCl + KCl = 51.14% Since the mixture only has NaCl and KCl, the mass percent of NaCl and KCl together in the mixture is 51.14%. Due to the lack of information about the ratio between NaCl and KCl in the mixture, and since the chloride ions were the only factor considered in the reaction to determine the percentages, we can't determine the mass percentage for each compound individually (NaCl and KCl).