Question

134 grams of nitric acid is added to 512 grams of water. Calculate the molality of nitric acid.

Answer 1

Answer:

0.004 m

Explanation:

Given data:

Mass of nitric acid = 132 g

Mass of water = 512 g

Molality of nitric acid = ?

Solution:

Formula:

Molality = number of moles of solute / mass of solvent in Kg

Number of moles of nitric acid:

Number of moles = mass/molar mass

Number of moles = 132 g/ 63.01 g/mol

Number of moles = 2.09 mol

Molality:

m = 2.09 mol / 512 Kg

m = 0.004 m

Answer 2

Answer:   4.15234 m

512 g H2O * $\frac{1 kg}{1000 g}$ = 0.512 kg H2O

Nitric Acid:  HNO3 = 1.008 + 14.007 + 3(15.999) = 63.012 g/mol

H = 1.008 g/mol

N = 14.007 g/mol

O3 = 3*15.999

134 g HNO₃ * $\frac{mol}{63.012 g}$ = 2.126 mol

m = $\frac{2.126 mol}{0.512 kg}$ = 4.15234 m