Concentrated nitric acid (HNO3) contains 70.3% HNO3 by mass. Calculate the volume of concentrated HNO3 needed to prepare 1.15L of 0.100M HNO3 stock solution. (density HNO3 = 1.41 g/cm3)

1) Calculate the number of moles in 1.15 liter of 0.100 M HNO3 solution.

M = n / V = > n = M*V = 0.100M * 1.15 l = 0.115 moles

2) Calculate the mass of 0.115 moles of HNO3

mass = number of moles * molar mass

molar mass of HNO3 = 1.00 g/mol + 14.0 g/mol + 3*16.0g/mol = 63.0 g/mol

mass = 0.115 mol * 63.0g/mol = 7.245 g

3) Calculate the mass of 70.3% HNO3 solution that contains 7.245 grams of HNO3

% = (mass of solute / mass of solution) * 100

=> mass of solution = mass of solute * 100 / % = 7.245 g * 100 / 70.3%

mass of soltuion = 10.3 g.

4) Convert 10.3 grams of HNO3 solution into volume, using density, D

D = mass / Volume = > Volume = mass / D

=. Volume = 10.3 g / 1.41 g/cm^3 = 7.30 cm^3

Answer: 7.30 cm^3