Final answer:
The percent by mass of CdSO4 in a 1.0 molal solution can be calculated using the molar mass of CdSO4, the mass of water as the solvent, and considering the total mass of the solution. Additionally, concepts such as common ion effect, solubility product constant (Ksp), and chemical equilibrium play significant roles in solubility and precipitation reactions in various scenarios.
Step-by-step explanation:
The student's question pertains to finding the percent by mass of CdSO4 in a 1.0 molal aqueous solution. The percent by mass is calculated using the formula: percent by mass = (mass of solute / mass of solution) × 100%. First, it is essential to know the molar mass of CdSO4, which can be found by adding the atomic masses of cadmium (Cd), sulfur (S), and four oxygen (O) atoms. Assuming the density of water is close to 1 g/mL, for a molal solution, the mass of the solute (CdSO4) for 1.0 mol is equal to its molar mass, and the mass of the solvent (water) for 1 molal solution is 1 kg (or 1000 g). The total mass of the solution is hence the sum of the mass of the solvent and the mass of the solute.
To address the additional inquiries, the common ion effect and how it impacts the solubility of compounds like cadmium sulfide (CdS) in a solution containing a common ion such as cadmium bromide (CdBr₂) are considered. The solubility product constant (Ksp) for CdS can help calculate molar solubility in such scenarios. Additionally, the adjustment of concentrations and precipitation conditions after adding strong bases such as NaOH, which alters the ionic equilibrium in the solution, is also a practical example of applying chemical equilibrium concepts.