Answer:
[HNO₃] = 0.39 m
Step-by-step explanation:
Let's analyse the information given.
2.44 % mass is the grams of solute in 100 g of solution. In this case, the solution has 2.44 g of HNO₃
In this case, we do not have to use density, because we have solution mass and solute mass.
Total mass of solution = Solute mass +Solvent mass
100 g = 2.44 g + Solvent mass
100 g - 2.44 g = 97.56 g → Solvent mass.
To find molality we have to convert solvent mass in g to kg
97.56 g . 1kg/1000 g = 0.09756 kg
And afterwards, the mass of solute into moles (mass / molar mass)
These steps can be done in an indistinct order. The important thing is that the molality implies the ratio of solute moles between 1 kg of solvent.
2.44 g / 63 g/mol = 0.0387 moles.
Molality = mol /kg → 0.0387 mol / 0.09756 kg = 0.39 m