What is the molality of sodium chloride in solution that is 13.0% by mass sodium chloride and that has a density of 1.10 g/mL?
A)2.23
B)1.30
C)2.56
D)2.03
E)1.10

Question

Quizplus · Accepted Answer

Molality (m) is defined as the number of moles of solute per kilogram of solvent.

First, we need to calculate the mass of the solution:

mass of solution = mass of solute + mass of solvent

Let's assume we have 100 g of solution, then:

mass of sodium chloride = 13.0 g 
mass of solvent = 100 g - 13.0 g = 87.0 g

Next, we need to calculate the number of moles of sodium chloride:

moles of NaCl = mass of NaCl / molar mass of NaCl 
moles of NaCl = 13.0 g / 58.44 g/mol (molar mass of NaCl) 
moles of NaCl = 0.222 mol

Finally, we can calculate the molality:

molality = moles of solute / kg of solvent 
molality = 0.222 mol / 0.087 kg 
molality = 2.56 mol/kg

Therefore, the answer is C) 2.56.

What Is the Molality of Sodium Chloride in Solution That