key term - Solubility equilibrium

Definition

Solubility equilibrium refers to the dynamic balance established between the dissolved ions of a solute and the undissolved solid in a saturated solution. At this point, the rate of dissolution of the solid equals the rate of precipitation, meaning that the concentration of the solute remains constant. This equilibrium is influenced by various factors, including temperature, pressure, and the presence of other ions in solution.

5 Must Know Facts For Your Next Test

1. In solubility equilibrium, the concentration of dissolved ions remains constant over time as long as conditions are stable.
2. The solubility product constant (Ksp) can be used to calculate how much of a solid will dissolve in water before reaching equilibrium.
3. The common ion effect occurs when an ion common to a saturated solution is added, leading to a decrease in solubility of the solid due to shifting the equilibrium.
4. Precipitation reactions involve forming solid from soluble ions in solution, often driven by changes in concentration or the introduction of common ions.
5. Temperature changes can affect solubility; typically, an increase in temperature increases solubility for most solids but may decrease it for some gases.

Review Questions

• How does the addition of a common ion affect the solubility equilibrium of a salt?
  • The addition of a common ion to a solution at solubility equilibrium causes the system to shift according to Le Chatelier's Principle. This means that the equilibrium will shift toward the formation of more undissolved solid, leading to a decrease in the overall solubility of that salt. As a result, less of the salt will dissolve into solution because the presence of the common ion drives the reaction toward precipitation.
• Discuss how temperature impacts solubility equilibria for different types of substances.
  • Temperature plays a significant role in solubility equilibria, generally increasing solubility for most ionic solids as temperature rises. However, this trend can differ for gases; for example, gases tend to become less soluble as temperature increases. Understanding these effects helps predict how changing conditions can impact whether a substance will remain dissolved or precipitate out of solution.
• Evaluate how solubility equilibria are applied in real-world scenarios such as water treatment and pharmaceuticals.
  • Solubility equilibria are crucial in applications like water treatment and pharmaceuticals, where controlling ion concentrations can lead to effective removal or recovery of substances. In water treatment, understanding how certain ions interact can help optimize processes like precipitation to remove contaminants. In pharmaceuticals, designing drugs with appropriate solubility ensures effective delivery and absorption within the body. By evaluating these equilibria, professionals can enhance effectiveness while minimizing waste and side effects.

Related terms

Ksp:

Ksp, or the solubility product constant, is a specific type of equilibrium constant that quantifies the solubility of a sparingly soluble ionic compound in water.

Le Chatelier's Principle:

Le Chatelier's Principle states that if a system at equilibrium is disturbed by a change in concentration, temperature, or pressure, the system will shift to counteract that disturbance and restore a new equilibrium.

saturation: Saturation occurs when a solution contains the maximum concentration of solute that can dissolve at a given temperature and pressure, beyond which any additional solute will not dissolve.