Question

the molality of 1 M solution of sodium nitrate is 0.8 mol/kg .determine the density of the solution.

Answer 1

use firmula if calculating the density

Answer 2

Answer : The density of solution is, 0.1062 g/ml

Solution : Given,

Molarity of solution = 1 M = 1 mole/L

Molality of solution = 0.8 mole/Kg

Molar mass of sodium nitrate = 84.99 g/mole

The relation between the molarity, molality and the density of the solution is,

$d=M[\frac{1}{m}+\frac{M_b}{1000}]$

where,

d = density of solution

m = molality of solution

M = molarity of solution

$M_b$ = molar mass of solute, sodium nitrate

Now put all the given values in the above formula, we get the density of solution.

$d=1mole/L[\frac{1}{0.8mole/Kg}+\frac{84.99Kg/mole}{1000}]=0.1062Kg/L=0.1062g/ml$

Therefore, the density of solution is, 0.1062 g/ml