Let's consider a solution made by dissolving 2.355 g of sulfuric acid, H 2SO4, in water. The total volume of the solution is 50.0 mL. What is the molar concentration of sulfuric acid, [H2SO4]?
We’re being asked to calculate the molarity (M) of a solution of H2SO4. Recall that molarity is the ratio of the moles of solute and the volume of solution (in liters). In other words:
We first need to determine the number of moles of H2SO4 since this is the only information missing for us to find molarity. Notice that the volume of the solution is already given.
We’re given the mass of H2SO4. We can use the molar mass of H2SO4 to find the moles.
The molar mass of H2SO4 is:
H2SO4 2 H x 1.008 g/mol H = 2.016 g/mol
1 S x 32.07 g/mol S = 32.07 g/mol
4 O x 16.00 g/mol O = 64.00 g/mol
Molar mass = 98.086g/ 1 mol H2SO4