At 70 °C, a solution of 30 g of NH3 in 100 g of H2O, is supersaturated. How much NH3 will bubble away if the temperature is lowered to 10 °C?
30 g NH3
22 g NH3
20 g NH3
0 g NH3 because the solution becomes unsaturated.
0 g NH3 because the solution becomes unsaturated.
When the temperature is lowered from 70 °C to 10 °C, the solubility of NH3 in water decreases. This will cause the excess NH3 that was previously dissolved in the supersaturated solution at 70 °C to no longer be soluble at 10 °C, resulting in it bubbling away. Since the solution is now unsaturated at 10 °C, it will not be able to hold onto the NH3 that was previously dissolved in excess at 70 °C.