Question

An aqueous solution that is 20.0 percent sulfuric acid (h2so4) by mass has a density of 1.105 g/ml. determine the molarity of the solution.

Answer 1

The definition of molarity is:

Molarity = moles of solute / total volume of solution in Liters

In this case, our solute is Sulfuric Acid. To solve this problem, let us assume a basis for calculation.

Let us say that,

Total mass of solution = 100 g

Therefore mass of H2SO4 = 20 g

The molar mass of H2SO4 = 98.079 g / mol

 

Calculating for number of moles of H2SO4:

number of moles = 20 g / (98.079 g / mol)

number of moles = 0.204 mol

 

Calculating for the volume of solution using the density:

total volume of solution = 100 g / (1.105 g / mL)

total volume of solution = 90.50 mL = 0.0905 L

 

Therefore the molarity is:

Molarity = 0.204 mol / 0.0905 L

Molarity = 2.2542 mol / L

Molarity = 2.25 M