What is the molality of a 10.0 % by mass solution of NaCl? (molar mass of NaCl = 58.44 g/mol) ______ mol/kg Your answer should be rounded to three significant figures. Do not include units in your answer.

To solve this problem, we need to follow these steps:

1. Understand that a 10.0% by mass solution means that there are 10.0 g of NaCl in 100 g of solution.

2. Convert the mass of the solution to kg, because molality is defined as the number of moles of solute per kilogram of solvent. Since the solution is assumed to be water, and the density of water is approximately 1 g/mL, 100 g of water is approximately 100 mL, or 0.1 kg.

3. Calculate the number of moles of NaCl. We know that the molar mass of NaCl is 58.44 g/mol, so 10.0 g of NaCl is (10.0 g) / (58.44 g/mol) = 0.171 moles.

4. Finally, calculate the molality. Molality (m) is defined as the number of moles of solute (NaCl) divided by the mass of the solvent (water) in kg. So, m = (0.171 moles) / (0.1 kg) = 1.71 mol/kg.

So, the molality of a 10.0% by mass solution of NaCl is 1.71 mol/kg.