Question

Find the molarity of a 40.0% by mass aqueous solution of sulfuric acid, H₂SO₄, for which the density is 1.3057 g/mL.

A) 2.14 M
B) 3.25 M
C) 4.60 M
D) 5.80 M

Answer 1

To find the molarity of a 40.0% by mass sulfuric acid solution with a given density, calculate the mass of sulfuric acid in 1 liter of the solution, convert it to moles using the molar mass of sulfuric acid, and then divide by the volume in liters. The molarity is roughly 5.32 M.

Step-by-step explanation:

To find the molarity of a 40.0% by mass aqueous solution of sulfuric acid (H₂SO₄) with a density of 1.3057 g/mL, we can follow these steps:

1. Calculate the mass of 1 liter of the solution:
   
   1,000 mL × 1.3057 g/mL = 1,305.7 grams
2. Determine the mass of H₂SO₄ in 1 liter of the solution:
   
   40.0% of 1,305.7 g = 522.28 grams
3. Calculate the number of moles of H₂SO₄:
   
   Using the molecular mass of H₂SO₄ (98.08 g/mol),
   
   522.28 g ÷ 98.08 g/mol = approximately 5.32 moles
4. Since we have the volume as 1 liter, the molarity is the same as the number of moles:
   
   Molarity = 5.32 moles/liter = 5.32 M

Therefore, the molarity of the solution is roughly 5.32 M, which was not provided in the answer choices, suggesting a calculation or typographical error.