Final answer:
The mass percent of ammonium chloride in a 0.756 M aqueous solution with a density of 1.0107 g/mL is approximately 4.00%. This is calculated by multiplying the molarity by the molar mass to find the mass of solute per liter, which is then divided by the mass of the solution per liter, and multiplied by 100 to get the percent.
Step-by-step explanation:
To calculate the mass percent of ammonium chloride in the solution, we need to know the mass of ammonium chloride in a given volume of the solution as well as the mass of the solution itself. From the question, we are told that the molarity (M) of the solution is 0.756 M, which means there are 0.756 moles of NH4Cl per liter of solution. The molar mass of NH4Cl is 53.50 g/mol, so one liter of this solution contains 0.756 moles * 53.50 g/mol = 40.446 g of NH4Cl.
The question also provides the density of the solution, which is 1.0107 g/mL. Therefore, the mass of 1 liter (1000 mL) of solution is 1.0107 g/mL * 1000 mL = 1010.7 g. Now, to find the mass percent of NH4Cl in the solution, we use the formula:
Mass percent = (mass of solute / mass of solution) * 100
Plugging in the values we have:
Mass percent = (40.446 g NH4Cl / 1010.7 g solution) * 100 ≈ 4.00%
So, the mass percent of ammonium chloride in the solution is approximately 4.00%.