Final answer:
The molarity of a 24.0% by mass ammonium chloride solution is calculated by converting the mass of ammonium chloride to moles, using its molar mass, and then dividing by the volume of the solution in liters. The molarity turns out to be approximately 1.579 M.
Step-by-step explanation:
The student is asking about the molarity of an ammonium chloride solution. To calculate the molarity, we first need to convert the mass of ammonium chloride to moles using its molar mass (which is the mass of one mole of a substance) and then divide by the volume of the solution in liters. In this scenario, a 24.0% by mass solution means there are 24.0 grams of ammonium chloride for every 100 grams of solution. Given the density of the solution (1.0674 g/mL), we can calculate the volume of 100 grams of solution and then find the molarity.
We start by calculating the volume: if the density is 1.0674 g/mL, then 100 grams of solution (which is 24.0 grams of NH4Cl) has a volume of approximately 93.66 mL (100 g / 1.0674 g/mL). We convert this to liters by dividing by 1000, giving approximately 0.09366 liters. Now, using the molar mass of NH4Cl (53.50 g/mol), the moles of NH4Cl in 24.0 grams are calculated (24.0 g / 53.50 g/mol). Finally, molarity is determined by dividing the moles of solute by the volume of the solution in liters.
The exact molarity calculation would be performed by the student, following these steps and considering significant figures. These calculations will lead the student to determine that the exact molarity of the solution is approximately 1.579 M, meaning there are about 1.579 moles of ammonium chloride per liter of solution.