Question

The solubility of a nonreactive gas in water increases with (a) an increase in gas pressure; (b) an increase in temperature; (c) increases in both temperature and pressure; (d) an increase in the volume of gas in equilibrium with the available water.

Short answer

In summary, (a) an increase in gas pressure will increase the solubility; (b) an increase in temperature will decrease the solubility; (c) increases in both temperature and pressure can either increase or decrease the solubility depending on the magnitude of changes in each; and (d) an increase in the volume of gas in equilibrium with the available water will not change the solubility unless the pressure also increases.

Step-by-step solution

Effect of an Increase in Gas Pressure

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, when gas pressure increases, the solubility of the gas in the water also increases.

Effect of an Increase in Temperature

Increasing the temperature typically decreases the solubility of a gas in a liquid. This is because when a system is heated, it tends to favor the side of the reaction that absorbs heat, which is the side of the gas. Therefore, an increase in temperature will decrease the solubility of the gas in the water.

Effect of Increases in Both Temperature and Pressure

The solubility of a gas in a liquid is affected by both temperature and pressure. An increase in pressure increases the solubility of the gas, while an increase in temperature decreases it. However, how much each factor can influence the overall solubility depends on the magnitude of the changes in pressure and temperature. In some cases, a substantial increase in pressure can offset a small increase in temperature.

Effect of an Increase in Volume of Gas in Equilibrium with the Available Water

An increase in volume of gas in equilibrium with the water might suggest that more gas molecules are present, and thus more could potentially dissolve. However, the key factor here is equilibrium - unless the pressure of the gas also increases, the amount of gas that can dissolve in the water at equilibrium will not change, no matter the volume of the gas.

Key concepts

Henry's Law

Understanding how gases dissolve in liquids can be fascinating, and Henry's law provides a fundamental explanation for this process. Imagine you're opening a soda bottle; the fizz that escapes provides a clue to this law in action. Henry's law states that at a constant temperature, the amount of gas that dissolves in a liquid is proportional to the pressure of that gas above the liquid. In simpler terms, the higher the pressure, the more gas can be dissolved.

This relationship is crucial in various applications, from carbonation of beverages to the way fish get oxygen in water. Henry's law can be expressed by the equation: \(C = kP\), where \(C\) is the concentration of the dissolved gas, \(k\) is Henry's law constant, and \(P\) is the partial pressure of the gas above the liquid. It's worth noting that this constant, \(k\), can vary depending on the gas and the liquid involved, as well as the temperature.

When the pressure increases, more gas molecules collide with the liquid's surface, which increases the chance that these molecules will dissolve. It is why shaking a soda bottle increases the pressure, resulting in a more vigorous fizz when you open it - a lot more gas has dissolved due to the increased pressure.

Effect of Temperature on Gas Solubility

Temperature plays a crucial role in the dissolving process of gases in liquids. Unlike solids that typically dissolve better in warm liquids, gases tend to be less soluble in liquids as the temperature increases.

As you heat a liquid, the molecules within it move faster and create more space between them. This extra space allows gas molecules to escape more easily, leading to decreased solubility. The term scientists use for this is exothermic disassociation; essentially, when the liquid absorbs heat, the dissolved gas is released.

This concept has real-world implications, particularly in aquatic environments. For instance, warmer rivers and lakes can hold less oxygen, which affects fish and other aquatic life. Also, it's integral to understanding and predicting the impact of temperature change on gas-liquid systems in industrial processes.

When diving into deep waters, divers must consider that cooler water temperatures increase gas solubility, which affects how much nitrogen dissolves in their blood and poses a risk for decompression sickness, also known as 'the bends.' Thus, both divers and engineers must understand the intricacies of the temperature's impact on gas solubility for safety and effectiveness.

Gas-Liquid Equilibrium

The concept of gas-liquid equilibrium is about balance. At a certain point, the rate at which gas molecules dissolve in a liquid is equal to the rate they escape back into the gas phase. When this balance is achieved, we say the system has reached equilibrium.

A change in pressure or temperature can disturb this equilibrium. Increase the pressure, and more gas dissolves until a new equilibrium is established. Raise the temperature, and more gas escapes until equilibrium is reestablished at a lower concentration of dissolved gas.

Understanding equilibrium is essential not just in academic settings but also in industries such as brewing, where equilibrium between carbon dioxide and beer is vital for the right fizz, and in the design of life-support systems in submarines or spacecraft where maintaining correct levels of dissolved gases is crucial for habitability.

In recreational activities like scuba diving, controlling the ascent rate is essential to prevent gases from coming out of solution too quickly as the pressure decreases, avoiding decompression sickness. Through the lens of gas-liquid equilibrium, we see how balancing intricate factors is key to both nature and numerous technological applications.