1. NH 3 has a solubility of 60g at 18 0 C in 100.0mLof water. KNO 3 has a solubility of 60g at 38 0 C in 100.0mLof water. HCl has a solubility of 60g at 48 0 C in 100.0mLof water. NH 4 Cl has a solubility of 60g at 66 o C in 100.0g water. KClO 3 has a solubility of 60g at 100 o C in 100.0g water.

2. NH 3 has a solubility of 60g at 18 0 C in 100.0mLof water. KNO 3 has a solubility of 60g at 38 0 C in 100.0mLof water. HCl has a solubility of 60g at 48 0 C in 100.0mLof water. NH 4 Cl has a solubility of 60g at 66 o C in 100.0g water. KClO 3 has a solubility of 60g at 100 o C in 100.0g water.

3. The solubility of NaNO 3 at 27 o C is about 94g in 100mL of water. The solubility of NaNO 3 at 52 0 C is 120g in 100mL of water. As you see from the graph the solubility of NaNO 3 INCREASES as temperature INCREASES. This is due to the fact that the dissolving of this salt is ENDOTHERMIC, energy absorbing, q is +.

4. At 10 o C NH 3 has a solubility of 70 grams of NH 3 in 100 grams of water. At 70 o C NH 3 has a solubility of 19 grams of NH 3 in 100 grams of water. The solubility of NH3 DECREASES as the temperature INCREASES, Therefore the dissolving of ammonia is EXOTHERMIC – it cannot give off heat at higher temperatures which hinders dissolving. The heat transfer is negative (-q) for this reaction. This is typical of gasses which dissolve poorly at higher temps.

5. U DO IT NOW 1/29/07 1.What will occur if NaNO 3 is cooled from 52 o C to 27 o C? 2.Which is the most soluble substance at 37 o C, which is the least soluble. 3.Identify the gases in the table. 4. What will occur as the temp. of NH 3 (aq) in solution is increased from 10 o C to 70 o C?

6. The solubility of NaNO 3 at 27 o C HOLDS about 94g in 100mL of water. The solubility of NaNO 3 at 52 0 C HOLDS 120g in 100mL of water. As the temperature drops from 52 o C to 27 o C the solubility drops from 120g to 94g. The difference of 26g will precipitate out as a solid on the bottom of the vessel. The 120g that is saturated at 52 o C is supersaturated at 27 o C. At 27 o C only 94 g can dissolve, 26g of the 120g must precipitate to reach 94g. (52 0 C,120g) (27 0 C, 94g)

7. At 52 o C 120g of NaNO 3 will dissolve, the solution has 120g in 100g water. The electrostatic attractions to begin to form the ionic crystal lattice. COOLING A precipitate forms. Energy is needed to break the electrostatic attractions of the lattice, (lattice energy) The solution that could carry 120g at 52 o C cannot hold that much at lower tamps precipitate will form as it cools. COOLING CAUSES