Identify if solubility increases/decreases/stays the same in the following statements. Each statement refers to the solubility of the solute mentioned.
Increasing the temperature of a solution of a salt that has an enthalpy of solution of 0.0 kJ/mol.
Reducing the partial pressure of nitrogen gas over a solution of nitrogen dissolved in hexane.
Reducing the temperature of a solution of oxygen dissolved in lake water.
Changing the solvent for a solution of CH3OH from pentanol(C5H11OH) to ethanol(C2H5OH)
Increasing the temperature of a solution of KOH dissolved in water. This salt has an exothermic enthalpy of solution.
Increasing the overall pressure on a solution of NaCl dissolved in water.
Raising the partial pressure of CO2 gas on a solution of CO2 dissolved in water.
To determine whether solubility increases, decreases, or stays the same in each statement, we need to consider the factors that affect solubility. These factors include temperature, pressure, and the nature of the solute and solvent.
1. Increasing the temperature of a solution of a salt with an enthalpy of solution of 0.0 kJ/mol:
Solubility generally increases with an increase in temperature for most salts, as higher temperatures provide more energy for the solute particles to dissolve. Therefore, in this case, the solubility of the salt would increase.
2. Reducing the partial pressure of nitrogen gas over a solution of nitrogen dissolved in hexane:
By reducing the partial pressure of the gas, we decrease the driving force for dissolution. As a result, the solubility of nitrogen in hexane would decrease.
3. Reducing the temperature of a solution of oxygen dissolved in lake water:
Most gases become less soluble in water as the temperature decreases. Therefore, the solubility of oxygen in lake water would decrease.
4. Changing the solvent for a solution of CH3OH from pentanol (C5H11OH) to ethanol (C2H5OH):
The nature of the solvent can significantly impact solubility. In this case, pentanol and ethanol have similar molecular structures and polarities. Therefore, the solubility of CH3OH is expected to stay the same when changing from pentanol to ethanol.
5. Increasing the temperature of a solution of KOH dissolved in water with an exothermic enthalpy of solution:
Exothermic enthalpies of solution release heat when the solute dissolves in the solvent. Increasing the temperature would counteract this heat release and decrease the solubility of KOH in water.
6. Increasing the overall pressure on a solution of NaCl dissolved in water:
In most cases, the solubility of solids like NaCl in water is not affected by changes in pressure. Therefore, increasing the overall pressure would have no significant effect on the solubility of NaCl in water.
7. Raising the partial pressure of CO2 gas on a solution of CO2 dissolved in water:
By increasing the partial pressure of the gas, we increase the driving force for dissolution. As a result, the solubility of CO2 in water would increase.