Final answer:
The solubility of gases decreases with higher temperatures due to increased molecular kinetic energy, and increases with higher pressure following Henry's Law. More solvent volume increases the absolute solubility but maintains the same solubility concentration unless temperature or pressure changes.
Step-by-step explanation:
When considering how the solubility of a gas in water is affected by temperature and pressure, we observe distinct behaviors. With an increase in temperature, the solubility of gases typically decreases. This is due to the enhanced kinetic energy that gas molecules possess at higher temperatures, which leads to an increased tendency for these molecules to escape from the aqueous phase back into the gas phase.
On the other hand, an increase in pressure leads to a higher solubility of gases. According to Henry's Law, the solubility of a gas in a liquid is directly proportional to the pressure of the gas above the liquid. Therefore, if more water is used as a solvent, the change in solubility would primarily depend on whether temperature or pressure is being altered. With more water volume at the same temperature and pressure, the absolute amount of gas that can be dissolved increases, though the concentration (amount of gas per unit volume) remains constant. If the temperature increases or the pressure decreases in a larger volume of water, the solubility decreases, and vice versa.