Question

The density of an aqueous solution of sulfuric acid is 1.36 g/mL and the concentration is 3.43 M. What is the concentration of this solution in percent by mass?

Answer 1

Answer:

2.40%

Explanation:

Density of a substance is given as the mass divided by the volume ,

Hence from the question ,

density of sulfuric acid = 1.35 g/mL

i.e.

1mL of sulfuric acid solution = 1.35 g of sulfuric acid ,

Hence,

1000mL of sulfuric acid solution = 1.35 * 1000 g of sulfuric acid,

i.e.

1000mL of sulfuric acid solution = 13500 g of sulfuric acid,

Now, Molarity of a solution is given by the moles of solute per liter of the solution .

Hence,

M = moles of solute / volume of solution (in L)

From question , '

3.43 M of sulfuric acid ,

Hence,

In 1 L of solution , 3.34 moles of sulfuric acid are present,

Now,

Moles are calculated as the given mass divided by the molecular mass.

The molecular mass of sulfuric acid is 98 g /mol

moles = ( mass / molecular mass )

therefore,

mass = moles * molecular mass

i.e.

mass of sulfuric acid = 3.34 mol * 98 g/mol = 327.32 g

Now, to calculate the mass percentage of sulfuric acid , is given by the mass of sulfuric acid divided by the mass of the total solution multiplied by 100.

therefore,

mass of sulfuric acid = 327.32 / 13600 * 100

Hence, mass of sulfuric acid = 2.40%