Question

A chemistry student is given 650. mL of a clear aqueous solution at 33.°C. He is told an unknown amount of a certain compound X is dissolved in the solution. The student allows the solution to cool to 17.9 0C. At that point, the student sees that a precipitate has formed. He pours off the remaining liquid solution, throws away the precipitates, and evaporates the water from the remaining liquid solution under vacuum. More precipitate forms. The student washes, dries and weighs the additional precipitate. It weighs 0.150 kg.

1. Using only the information above, can you calculate the solubility of X in water at 17 0C.
2. If you said yes, calculate it.

Answer 1

No, you can not calculate the solubility of X in water at 17 0C.

Step-by-step explanation:

Solubility refers to the amount of a substance that dissolves in 1000 L of water.

To calculate the solubility of a solute in water, all the water is evaporated and the solid is carefully collected, washed, dried and weighed. The mass of solid obtained can now be used to calculate the solubility of the solute in water as long as there was no loss in mass of solid during the experiment.

In this case, the student threw away part of the solid that precipitated. As a result of this, the mass of solid obtained at the end of the experiment is not exactly the total mass of solute that dissolved in the solvent. Hence, the solubility of X in water at 17 0C can not be accurately calculated.