- Experimental Procedure
Place about 5 grams of the compound of interest in a clean, standard taper 14/20 size D Buchner type filter funnel (Ace catalog number 9439-08). Dry the funnel and sample for one hour in a 120°C oven, allow to cool to room temperature, and then weigh the funnel and contents. Insert the funnel into a 14/20 500-mL round bottom flask and attach to a trap that is attached to an aspirator. Fill a 500-mL separatory funnel with distilled water using a graduated cylinder. Drip the water from the funnel onto the compound in the filter (stirring gently with a glass rod) using vacuum filtration. The drip rate should be about 10-20 drops per second. There should be approximately 1/4 inch of water above the compound at all times. When the separatory funnel is empty, fill it once more with 500 mL of distilled water. Drip the water through the funnel. When all the water has passed through the compound in the filter funnel, continue suctioning for a few minutes and then place the funnel with the compound in the oven for two hours. After cooling, reweigh. The loss in weight represents the solubility of the barium salt in 1000 mL of water.
If the compound has a solubility of greater than 3 g per liter, place about 15 grams of the compound in a clean, standard taper 14/20 size D Buchner type filter funnel (Ace catalog number 9439-08) and continue as above except that only 100 mL of water should be passed through the compound.
- Typical Results
As an example of the results obtained by students, the following data are presented. For barium phosphate: 0.0369 g/L, 0.0527 g/L, 0.0381 g/L; for calcium sulfate dihdrate: 2.03 g/L, 1.98 g/L, and 1.98 g/L.