Solubility Equilibria and Equilibrium Constants

These flashcards cover key concepts related to solubility equilibria, equilibrium constants, and factors influencing solubility in various contexts.

What is chemical equilibrium?

The rates of the forward and reverse reactions are equal and concentrations of reactants and products remain constant.

What does the equilibrium constant (K) depend on?

K depends on the particular reaction and temperature.

What is the form of the equilibrium constant expression?

K = [Products]^{coefficients} / [Reactants]^{coefficients}.

Why are solids omitted from the equilibrium constant expression?

The concentration of a solid is fixed and does not change.

What principle explains the response of an equilibrium system to stress?

Le Chatelier’s Principle.

What happens if the concentration of a reactant is increased in a reaction at equilibrium?

The equilibrium will shift towards the products.

How does a change in temperature affect equilibrium?

It can shift the equilibrium position either towards products or reactants, depending on whether the reaction is exothermic or endothermic.

What is the solubility product (Ksp)?

The constant for the equilibrium established between a solid solute and its ions in a saturated solution.

Give an example of a common ion effect on solubility.

Adding NaCl decreases the solubility of AgCl because both produce Cl- ions.

In what units is molar solubility typically expressed?

Moles per liter (mol/L).

How is Ksp calculated from molar solubility for CaF2?

Ksp = [Ca^{2+}][F^{-}]^{2}, and if molar solubility is s, then Ksp = s(2s)^{2}.

What does a large K value (K >> 1) indicate about the reaction?

It indicates that products are favored at equilibrium.

What does a small K value (K << 1) indicate about the reaction?

It indicates that reactants are favored at equilibrium.

Explain the importance of pH on solubility regarding Mg(OH)2.

Increasing pH increases [OH^{-}] and shifts equilibrium left, reducing the solubility of Mg(OH)2.

What happens to the solubility of Ag3PO4 in acidic conditions?

The solubility increases due to H+ ions reacting with PO4^{3-}.

What is dynamic equilibrium in saturated solutions?

The rate of dissolution equals the rate of precipitation, and concentrations remain constant.

What can you conclude about solubility product values at a given temperature?

Ksp has only one value for a given solid at a specific temperature.

Why is Ksp not reliable for comparing solubility of salts that produce different numbers of ions?

Different salts with different ion numbers yield different stoichiometry, affecting solubility.

What is the relationship between molar solubility and Ksp for salts producing the same number of ions?

Higher Ksp values correspond to greater molar solubility.

What happens to the solubility of a salt when a common ion is present?

The solubility generally decreases due to a shift in equilibrium.

What effect does increasing the concentration of products have on the equilibrium position?

It shifts the equilibrium to the left, favoring the reactants.

How are equilibrium constants expressed for heterogeneous equilibria?

Concentrations of pure solids and liquids are omitted from the expressions.

What is the equilibrium expression for copper arsenate (Cu3(AsO4)2)?

Ksp = [Cu^{2+}]^{3}[AsO4^{3-}]^{2}.

What are the applications of the solubility product principle?

Understanding precipitation, ion interactions, and drug design.

How does drought affect the solubility of minerals in water?

Decreases solubility by reducing the fluid in which minerals can dissolve.

Identify a process where the common ion effect is utilized.

Limit the solubility of Ag2CrO4 by using AgNO3 which introduces Ag+ ions.

What is the role of fluorapatite in dental health?

Fluorapatite is less soluble than hydroxyapatite and helps prevent tooth decay.

What can a low Ksp indicate in the context of drug solubility?

It may allow certain drugs to be less absorbed in the body, minimizing toxicity.

Explain how solubility can be manipulated in drug development.

Modifying the drug salt form can alter its solubility properties.

What is a potential consequence of poor salt solubility in formulations?

Poorly soluble salts may precipitate and become less available for absorption.

Why is understanding pH crucial when considering solubility?

Changes in pH can facilitate or hinder the solubility of various compounds.

How does temperature typically influence solubility?

In general, solubility increases with an increase in temperature for solids.

What is the significance of common ion effect in industrial applications?

It helps design processes in mining and separation techniques.

Explain a scenario where a reaction could be pushed toward product formation using Le Chatelier’s Principle.

Increasing temperature in an endothermic reaction will favor product formation.

What happens when the concentration of a liquid is changed in an equilibrium reaction?

The liquid concentration is typically not included in the K expression and does not affect K.

How can dynamic equilibria be disrupted?

By adding a stress such as changing concentration, pressure, or temperature.

What does it mean if a salt has a very low solubility?

It may be beneficial in clinical settings as it minimizes systemic absorption.

Define molar solubility.

The number of moles of solute that can dissolve in one liter of solution at saturation.

What is the effect of increasing temperature on gas solubility in liquids?

Gas solubility generally decreases with an increase in temperature.

What happens to the solubility of salts when an acid is introduced?

The solubility may increase due to the reaction of the acid with certain ions.

Why is the common ion effect relevant to environmental science?

It illustrates how ions in natural waters affect the solubility of minerals.

What factors can alter the Ksp of a substance?

Temperature and the presence of other ions can alter Ksp.

Discuss how concentration changes can aid in solubility modelling in pharmaceuticals.

Understanding concentration-response relationships can improve drug formulations.