Answer:
Density of solution = 1.43 g/mL
Molality → mol/kg = 37 m
Explanation:
The solute is HNO₃
Molar mass → 63 g/mol
70 % by mass → 70 g of solute / 100 g of solution
We convert the mass of HNO₃ to moles → 70 g / 63 g/mol = 1.11 moles
So let's apply molarity to find out the volume of our moles.
Molarity (M) = mol/L → mol / M = L → 1.11 mol / 15.9 M = 0.070 L
This is the volume for solution. We can convert it from L to mL
0.070 L . 1000 mL / 1L = 70 mL
As the mass of solution = 100 g → Density = Mass/Volume
100g / 70 mL = 1.43 g/mL
Molality → mol of solute / kg of solvent
Solution mass = 100 g → Mass of solute + Mass of solvent
Mass of solvent = 30 g
We convert the mass of solvent from g to kg → 30 g . 1kg / 1000 g = 0.030 kg
Molality (mol/kg) → 1.11 mol / 0.030 kg = 37 m
