|AP Chemistry - Impure Samples and Percentage Purity Worksheet|
|1.||An impure sample of Na2SO4 has
a mass of 1.56 grams. This sample is dissolved and allowed to react with BaCl2
solution. The precipitate has a mass of 2.15 grams. Calculate the percentage
of Na2SO4 in the original sample.
|2.||An impure, 0.500 gram sample of NaCl was dissolved
in 20.0 mL of water. The chloride ions were precipitated completely by addition
of a AgNO3 solution. The dried AgCl precipitate has a mass of
|a) How many moles of AgCl formed?|
|b) How many moles of NaCl were in the sample?|
|c) How many grams of NaCl were in the sample?|
|d) What was the percentage of NaCl in the impure sample?
|3.||An impure sample of Na2SO4 has
a mass of 1.65 grams and is dissolved in water. Addition of BaCl2
solution produced a precipitate of barium sulphate with mass 2.32 grams.
What is the percentage of Na2SO4 in the impure sample?
|4.||A sample known to contain only NaCl and KCl has a mass
of 1.08 grams. The sample is dissolved and treated with AgNO3
until precipitation is complete. The precipitate of AgCl has a mass of 2.32
grams. What is the percentage of NaCl in the mixture?
|5.||A mixture of Na2SO4 and K2SO4 having a total mass of 0.500 grams, was dissolved in water. Barium chloride was added as a precipitating agent. The dried BaSO4 resulting from the reaction has a mass of 0.715 grams. What is the percentage of each component in the original mixture?|