Question

Consider a system that consists of water and sodium chloride (NaCl) at room temperature and atmospheric pressure. The student is asked to determine the minimum amount of NaCl that needs to dissolve in 100 grams of water in order to form a saturated solution. The student should also calculate the molar solubility of NaCl in the solution.

Answer 1

To determine the minimum amount of NaCl needed to dissolve in 100 grams of water to form a saturated solution, we need to know the solubility of NaCl in water at room temperature  25C . The solubility of NaCl in water at 25C is approximately 357 grams per liter  g/L .First, we need to convert 100 grams of water to liters. The density of water at room temperature is approximately 1 g/mL or 1 g/cm. Therefore, 100 grams of water is equivalent to 100 mL or 0.1 L.Now, we can calculate the amount of NaCl needed to dissolve in 100 grams  0.1 L  of water to form a saturated solution:Amount of NaCl =  Solubility of NaCl    Volume of water Amount of NaCl =  357 g/L    0.1 L Amount of NaCl = 35.7 gSo, the minimum amount of NaCl needed to dissolve in 100 grams of water to form a saturated solution is 35.7 grams.Next, we need to calculate the molar solubility of NaCl in the solution. The molar mass of NaCl is approximately 58.44 g/mol.Molar solubility =  Amount of NaCl  /  Molar mass of NaCl Molar solubility =  35.7 g  /  58.44 g/mol Molar solubility  0.611 molTherefore, the molar solubility of NaCl in the saturated solution is approximately 0.611 mol.