By referring to Figure 13.15, determine the mass of each of the following salts required to form a saturated solution in 250 g of water at 30 °C: (b) Pb(NO₃)₂,

Key Concepts

Saturation and Solubility

Saturation refers to the point at which a solution can no longer dissolve additional solute at a given temperature and pressure. Solubility is the maximum amount of solute that can dissolve in a specific amount of solvent at a particular temperature. Understanding these concepts is crucial for determining how much of a salt, like Pb(NO3)2, can be dissolved in water.

Molar Mass Calculation

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). To find the mass of Pb(NO3)2 needed for a saturated solution, one must first calculate its molar mass by summing the atomic masses of its constituent elements. This calculation is essential for converting between moles and grams in stoichiometric problems.

Temperature Dependence of Solubility

The solubility of most salts varies with temperature; generally, solubility increases with rising temperature. For the question at hand, knowing that the solubility of Pb(NO3)2 at 30 °C is necessary to determine how much of the salt can be dissolved in 250 g of water. This relationship is key to solving the problem accurately.