Answer to Question #133900 in General Chemistry for rara

Question

From an 11.562-g sample containing sodium chloride, naphthalene, and sand, the following were recovered: 3.642 g sodium chloride, 1.564 g naphthalene, and 5.921 g sand. Calculate the percentage of each substance in the sample and the total percentage of sample recovered. If your calculations show less than 100% recovery, what could account for the difference? Show all your work.

Answer 1

Percentage of sodium chloride in the sample (3.642/11.562)X100

=31.5%

Percentage of Naphthalene in the sample (1.564/11.562)X100

=13.527%

Percentage of sand in the sample(5.921/11.562)X100

=51.211%

Total mass of sample recovered 3.642+1.564+5.921=11.127g

Total percentage of sample recovered (11.127/11.562)X100

=96.238%.

The difference in recovery is due to the loss of water of crystallization in sodium chloride crystals. In other words, some water molecules of crystallization were lost from the original sodium chloride through evaporation as heating is involved in the separation process.