Introduction to Solubility

Introduction to Solubility

• Science knows no country, knowledge belongs to humanity.
• This was stated by Louis Pasteur.

Solubility

• Solubility is the amount of solute that dissolves per liter of saturated solution.
• Slightly soluble ionic compounds only dissolve partially in solution.
• An equilibrium is formed between the solid and ions.

Solubility Equilibrium

• Saturated solution has solubility.
• Using the values of ions to calculate equilibrium (K_sp)

Examples of Solubility Equilibria and K_sp Values

• A table of different solutes along with their solubility equilibrium reaction and K_sp value at 25°C is provided.

Solubility: Type 1 Example

• Consider PbCl₂ dissolving in water.
• Calculate K_sp if molar solubility is 0.00130 mol/L.
• This shows a calculation process for K_sp using molar solubility.

Solubility: Type 2 Example

• Consider Ag₂CrO₄ dissolving in water.
• Calculate molar solubility if K_sp is 1.1×10⁻¹².
• This shows a calculation process for molar solubility using K_sp.

Solubility: Practice

• Identify the ionic compound with K_sp = 4s³ from a list of options.
• Shows the calculations behind finding the correct answer.

Precipitation Reaction

• Precipitation reaction occurs when two aqueous salt solutions are mixed and a precipitate forms.
• It's not a true equilibrium.

Predicting Precipitation

• Ways to predict if a precipitate will form is by knowing the solubility of inorganic compounds.
• Two categories: soluble and sparingly (slightly) soluble.

Solubility Rules

• Table outlining soluble and insoluble ionic compounds, and important exceptions.

Solubility: Practice Question

• Predict the outcome when sodium bromide and lead nitrate solutions are mixed.
• Shows the balanced chemical equation.
• The rules are referred to for determining if the outcome is soluble or insoluble.

Solubility and Q

• Q has the same formula as K_sp.
• Values are initial concentrations.
• Solutions and their characteristics based on how Q relates to K_sp: unsaturated, saturated, and supersaturated.

Solubility: Practice

• Determine the minimum [Cl⁻] required to begin precipation of Hg₂Cl₂ given [Hg₂²⁺] is 0.010 M

Solubility: Example 1

• Calculate the minimum [Cl⁻] required to begin precipitation of Hg₂Cl₂ given [Hg₂²⁺] is 0.010 M

Solubility

• The exothermic crystallization of supersaturated sodium acetate solutions is the chemistry behind reusable hand warmers.

Solubility: Example 2

• Calculate molar solubility of PbCrO₄ in 0.100 M Na₂CrO₄ if K_sp = 2.8 x 10⁻¹³.

Solubility: Practice

• Improve the quality of X-ray photos by adding compounds to a BaSO₄ suspension to control the Ba²⁺ concentration since Ba²⁺ is toxic.
• Determining the best compound from a list.

Solubility

• pH can affect the solubility of some compounds.
• Consider the Co(OH)₂ equilibrium example.

Solubility: Practice

• Determine how many compounds in a list would be less soluble in a pH 10.00 buffer than in pure water.

This quiz covers the fundamental concepts of solubility, including the definition, the formation of saturated solutions, and the principles of solubility equilibrium. It includes calculations related to the solubility product constant (K_sp) as well as practical examples for better understanding.