Question

calculate the mass concentration and molar concentration for 67.2% (by weight) nitric acid solution. The density of nitric acid solution (67.2% by weight) is 1.4 g/cm

Answer 1

consider 1 L of solution

volume = 1 L = 1000 mL

given:

density of solution = 1.4 g/cm^3 = 1.4 g/mL

So,

mass of solution = density * volume

= 1.4 g/mL * 1000 mL

= 1400 g

mass of HNO3 = 67.2 % of mass of solution

= 67.2 * 1400/100

= 940.8 g

mass concentration = mass / volume

= 940.8 g / 1000 mL

= 0.941 g/mL

Molar mass of HNO3,

MM = 1*MM(H) + 1*MM(N) + 3*MM(O)

= 1*1 + 1*14 + 3*16

= 63 g/mol

mass(HNO3)= 940.8 g

number of mol of HNO3,

n = mass/molar mass

=(940.8 g)/(63.02 g/mol)

= 14.9 mol

molar concentration = number of mol / volume in L

= 14.9 mol / 1 L

= 14.9 mol/L

Answer:

mass concentration = 0.941 g/mL

molar concentration = 14.9 mol/L