Calculate the more fraction molality and molarity of HNO3 in a solution containing 12.2% HNO3, Given density of HNO3=1.038 gcm-3 ,H=1,N=14, O =16
Answers
Given:
Density of HNO3 = 1.038 g/cm^-3
% mass of HNO3 = 12.2 %
To Find:
Mole fraction of the solution
Molality of the solution
Molarity of the solution
Solving:
Let us consider it to be a solution of 100 grams.
Mass of HNO3 in this solution = 12.2 grams
Mass of water = 100 - 12.2g = 87.8 grams
Converting into Kilograms we get:
= 87.8 / 1000
= 0.0878 kilograms
Calculating the molecular mass of water (H2O):
= 1 g x 2 + 16 g x 1
= 2 + 16
= 18 g mol^-1
Calculating the molecular mass of (HNO3):
= 1 g x 1 + 14 x 1 + 16 x 3
= 1 + 14 + 48
= 63 g mol^-1
Calculating number of moles of water:
= Given Mass / Molecular Mass
= 87.8 g / 18 g
= 4.8778 mol
Calculating number of moles of HNO3:
= Given Mass / Molecular Mass
= 12.2 g / 63 g
= 0.1937 mol
Calculating the total number of moles:
= 4.8778 mol + 0.1937 mol
= 5.0715 mol
Mole fraction of HNO3:
= nB/(nA + nB)
= 0.1937 mol / 5.0715 mol
= 0.0382 mol
Density of the solution = 1.038 g cm^-3
Calculating the volume of solution:
= Mass of solution / Density
= 100g / 1.038 g cm^-3
= 96.34 cm^3
= 96.34 mL
Converting in Liters we get:
= 96.34 / 1000
= 0.09634 Liters
Calculating the Molarity of the solution:
= Number of Moles of Solute / Number of Moles of solution in Liters
= 0.1937 / 0.09634
= 2.011 M
Calculating Molality:
= Number of moles of solute / Mass of solvent in kg
= 0.1937 mol / 0.0878 kg
= 2.206 mol kg^-1
Therefore, the mole fractions of HNO3 is 0.03802. The molarity of the solution is 2.011 mol L^-1. The molality of the solution is 2.206 mol kg^-1.
Answer:
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