A sample that is 74.5 percent chloride by mass is dissolved in water and treated with an excess of

AgNO3. If the mass of the AgCl precipitate is 1.115 g, what was the mass of the original sample?

Total mass of original sample = 0.38 g

Explanation:

Percentage of chloride = 74.5%

Mass of AgCl precipitate = 1.115 g

Mass of original sample = ?

Solution:

Mass of chloride:

1.115 g / 143.3 g/mol * 35.5 g/mol

0.0078 g * 35.5 = 0.28 g

Total mass of compound:

Total mass = mass of chloride / %of Cl * 100%

Total mass = 0.28 g / 74.5% * 100%

Total mass = 0.0038 g * 100

Total mass = 0.38 g