Kelarutan dan Hasil Kali Kelarutan (1) | Hubungan S dgn Ksp | Kimia Kelas 11

Summary

In this educational video, the host explains key concepts related to solubility and the solubility product constant (Ksp) in chemistry. Topics include understanding solubility (S), the relationship between solubility and Ksp, and how to calculate Ksp for various compounds. The video also covers how to determine the largest solubility from several substances, with practical examples such as the solubility of various salts in water. The explanation is supplemented with mathematical formulas and examples to clarify the concepts for chemistry students.

Takeaways

• 😀 Solubility (S) refers to the maximum concentration of solute that can dissolve in a solvent to form a saturated solution.
• 😀 Saturated solutions have the highest possible concentration of solute, and any excess solute will not dissolve.
• 😀 The formula for molarity (mol/L) is used to calculate solubility, either from moles of solute or mass of solute divided by the molar mass.
• 😀 The Solubility Product (Ksp) is an equilibrium constant used for saturated solutions to express the product of the concentrations of ions in the solution.
• 😀 For an ionic compound like CaF2, the Ksp is calculated by multiplying the concentrations of its ions, each raised to the power of its stoichiometric coefficient.
• 😀 The relationship between solubility (S) and Ksp for ionic compounds allows you to determine the solubility if the Ksp is known, or vice versa.
• 😀 For compounds like CaF2, the Ksp can be derived from the expression Ksp = 4S^3, where 'S' represents the solubility of the compound.
• 😀 Solubility can be compared among compounds using their Ksp values and the number of ions formed in solution (i.e., ion count).
• 😀 The compound with the largest Ksp value or the largest Ksp per ion count will generally have the highest solubility.
• 😀 To find the solubility (S) from Ksp, take the cube root (for compounds with 3 ions) or the fourth root (for compounds with 4 ions) of the Ksp value divided by a constant based on the stoichiometry.

Q & A

What is solubility (S) in a solution?

Solubility (S) refers to the maximum concentration of a solute that can dissolve in a solution at a specific temperature. It is also known as the concentration of a saturated solution.

What is the relationship between solubility and KSP (solubility product)?

KSP is the equilibrium constant for the dissolution of a solid solute in a saturated solution. The solubility of a compound (S) is directly related to KSP, with KSP representing the product of the concentrations of the ions in a saturated solution, each raised to the power of their respective coefficients.

How do you calculate solubility using the molarity formula?

To calculate solubility (S) using molarity, you use the formula: molarity (M) = moles of solute / volume of solution (in liters). Alternatively, if the mass of solute is known, you can use the formula: solubility (S) = mass of solute (g) / molar mass (Mr) × 1000 / volume of solution (mL).

What does KSP represent in a saturated solution?

KSP (solubility product) represents the equilibrium constant for a saturated solution, calculated by multiplying the concentrations of the dissolved ions, each raised to the power of their respective stoichiometric coefficients in the dissolution equation.

How can you derive the KSP expression for a compound like CaF2?

For CaF2, when it dissolves in water, it dissociates into Ca²⁺ and F⁻ ions. The KSP expression is the product of the concentrations of these ions, raised to the power of their coefficients in the dissolution equation: KSP = [Ca²⁺] × [F⁻]².

What does 'S' represent in the context of KSP calculations?

In KSP calculations, 'S' represents the solubility of the compound in mol/L (molarity). It is the concentration of the dissolved ions in a saturated solution.

How do you calculate KSP when you know the solubility (S) of a compound?

To calculate KSP when solubility (S) is known, use the appropriate stoichiometric relationship between the ions and their coefficients in the dissolution equation. For example, for a compound like CaF2 with solubility 'S', KSP = 4S³.

How do you determine the largest solubility among several compounds?

To determine which compound has the largest solubility, compare the value of KSP divided by the total number of ions in each compound. The compound with the highest KSP per ion count will have the largest solubility.

How do you calculate the mass of a compound like PbI2 dissolved in water, given its solubility?

To calculate the mass of PbI2 dissolved in water, first find the solubility (S) in mol/L, then use the formula: mass (g) = S (mol/L) × molar mass (g/mol) × volume (L).

What happens to the KSP value when the solubility of a compound increases?

As the solubility of a compound increases, the concentration of its ions increases, which leads to a higher KSP value, indicating a greater degree of dissociation in the solution.