Question

A solution of H2SO4(aq)H2SO4(aq) with a molal concentration of 2.55 m2.55 m has a density of 1.151 g/mL.1.151 g/mL. What is the molar concentration of this solution?

Answer 1

Answer:

Molar concentration = 2.35 M (Approx)

Explanation:

Given:

Density of solution = 1.151 g/ml

2.55 molal = 2.55 moles of solute/ kg

Find:

Molar concentration

Computation:

Molar mass of H2SO4 = 2(1.0079) + (32.066) + 4(15.999)

Molar mass of H2SO4 =  98.0778

Molar mass of H2SO4 = 98 g/mol (Approx)

Mass of solution = 2.55(98)g + 1000 g

Mass of solution = 1249.9 gm

Volume of solution = 1249.9 / 1.151 = 1086 ml

Volume of solution = 1.086 L

Molar concentration= 2.55 / 1.086

Molar concentration = 2.35 M (Approx)

Answer 2

Answer:

[H₂SO₄] = 2.35M

Explanation:

Our solute is the sulfuric acid → H₂SO₄

To determine the molar concentration we need the volume of solution.

Mass of solute: moles . molar mass

2.55 mol . 98 g/ 1 mol = 249.9 grams

Mass of solvent: 1 kg (we know this, because data refers about molality, moles of solute in 1kg of solvent)

Mass of solution = solute + solvent → 1000 g + 249.9 g = 1249.9 g

We apply density: Density = Mass / volume

1.151 g/mL = 1249.9 g / mL

mL = 1249.9 g/ 1.151 g/mL = 1086 mL

Molarity → mol/L → 2.55 moles/1.086L = 2.35 M