Question

What changes in temperature and pressure increase the solubility of a gas in solution?

Short answer

Increasing pressure will increase the solubility of a gas in a liquid. However, increasing the temperature will decrease the solubility of a gas in the liquid. Therefore, to maximize solubility, it is generally desirable to have high pressure and low temperature.

Step-by-step solution

Explain the effect of pressure on solubility

According to Henry's Law, the solubility of a gas in a liquid is directly proportional to the pressure of that gas above the liquid. Therefore, when the pressure increases, the solubility of the gas also increases.

Explain the effect of temperature on solubility

In contrast to solids and liquids, gas solubility decreases with an increase in temperature. This is because gas molecules have higher kinetic energy at higher temperatures and are more likely to escape from solution.

Summarize the conclusions

In summary, increasing the pressure will increase the solubility of a gas in a liquid. However, increasing the temperature will decrease the solubility of a gas in a liquid. Therefore, to maximize gas solubility one would want high pressure and low temperature.

Key concepts

Henry's Law

Henry's Law is a key principle that helps to understand the relationship between gas solubility and pressure. It states that the amount of gas dissolved in a liquid is directly proportional to the pressure of the gas above the liquid. This means that when the pressure of the gas increases, so does its solubility in the liquid.
For instance, if you have a bottle of carbonated soda, the carbon dioxide gas is kept dissolved in the soda by the high pressure in the sealed bottle. Once you open the bottle, the pressure is released, and the gas begins to escape, leading to the soda losing its fizz. This simple scenario illustrates how pressure affects the solubility of gases, as described by Henry's Law.

Temperature Effect on Solubility

Temperature has a significant impact on the solubility of gases, which behaves differently compared to solids and liquids. In general, when temperature increases, the solubility of a gas decreases. Why does this happen?
At higher temperatures, gas molecules gain more kinetic energy. This means they move faster and are more likely to leave the solution and enter the gaseous phase. Conversely, at lower temperatures, gas molecules have less kinetic energy and are more likely to remain dissolved in the liquid.

• High temperatures: Decrease gas solubility
• Low temperatures: Increase gas solubility

For example, cold bodies of water can hold more dissolved oxygen, which is crucial for aquatic life, compared to warmer waters.

Pressure Effect on Solubility

The effect of pressure on gas solubility is crucial in many practical applications. According to Henry's Law, an increase in pressure increases gas solubility in liquids. This is due to the reduced volume available for the gas molecules, which compresses them and forces more molecules into the liquid solution.
This principle finds applications in various fields such as scuba diving, where underwater environments with higher pressures can effectively dissolve more gases in the diver's blood. Similarly, in the food and beverage industry, increasing pressure is used to carbonate drinks by dissolving more carbon dioxide into them.
Overall, increasing the pressure is a method to enhance the solubility of gases, while reducing pressure does the opposite.