Introduction: Solubility is a substance’s ability to be dissolved in a liquid, usually water, and some substances are more soluble than others. A solution can be saturated, unsaturated or supersaturated. Temperature plays a large role in the solubility of substances. For example, on table G of the Chemistry reference tables it shows that 10g of KClO3 will dissolve in 100g of water at about 25°C, but at about 48°C, 20g will dissolve. The higher the temperature is, usually the more soluble a solute becomes, except when you’re talking about gasses. For example, NH3 becomes less soluble as the temperature rises. The relationship between solubility and temperature can be expressed by a solubility curve. A solubility curve is a graph of the solubility of a solute in grams per 100 grams of water (shown on the Y axis) at various temperatures in degrees Celsius (shown on the X Axis). Each solute has a different curve.
1. 2. 42g of unknown salt A (14g per trial) 3. 1 small beaker 4. 2 large beakers 5. 3 test tubes 6. Distilled water 7. Thermometer 8. Hot plate 9. Electronic balance 10. Stirring rod 11. Metal scoop 12. Graduated cylinder 13. Test tube racks 14. Tongs
Procedure: 1. Put some water into one of the large beakers and put it on the hot plate. Put ice water into the other one. 2. Measure out 14g of the unknown salt using the scoop and put it into one of the test tubes. 3. Measure 10mL of distilled water in the beaker. Then, transfer it to the graduated cylinder to make it easier to pour into the test tube. 4. When the water on the hot plate is boiling, use the tongs to lift the test tube into the hot water. Use the stirring rod to make the salt dissolve faster. 5. Once dissolved, replace the stirring rod with the thermometer and place the test tube into the ice water. Pay close attention and write the temperature at