Calculate the molality of a 27.0% (by mass)aqueous solution of nitric acid.
A)5.87
B)222
C)0.906
D)1.37
E)The density of the solution is needed to solve the problem.

Question

Quizplus · Accepted Answer

The molality (m) of a solution is defined as the number of moles of solute per kilogram of solvent. In this case, the solute is nitric acid (HNO3), which has a molar mass of approximately 63.01 g/mol. A 27.0% by mass solution means there are 27.0 grams of HNO3 in 100 grams of solution. Therefore, the mass of the solvent (water) is 100 g - 27.0 g = 73.0 g = 0.073 kg. The number of moles of HNO3 is 27.0 g / 63.01 g/mol = 0.4286 mol. The molality is then 0.4286 mol / 0.073 kg = 5.87 mol/kg.

Calculate the Molality of a 27