Question

A solution of H2SO4(aq) with a molal concentration of 5.74 m has a density of 1.238 g/mL. What is the molar concentration of this solution?

Answer 1

molality: m
number of moles of solute: n
Molarity: M
density of solution: d
V = volume of solution in liters
K = mass of solvent in Kg
W: molar mass of solute


Formulas:

m = n/K
M = n / V

M = d*m / (1 + m*W)

d = 1.238 g/mL = 1.238 kg/liter
m = 5.74
W H2SO4 = 2*1g/mol + 32g/mol + 4*16g/mol = 98 g/mol = 0.098 kg/mol

M = (1.238 kg/liter * 5.74 mol/kg) / (1 + 5.74 mol/kg * 0.098g/mol) = 4.55

Answer: 4.55