chemisty 2 question

Question

A concentrated solution of sulfuric acid has a density of 1.72g/mL and contains 79.7% sulfuric acid by mass. A 75 mL quantity of concentrated sulfuric acid is diluted with water to make a final solution with a volume of 5.00 L. What is the molar concentration of sulfuric acid in the dilute solution? The molar mass of sulfuric acid is 98.08 g/mol.

Answer 1

75 ml x 1.72 g/ml = 129 g of concentrated solution of H2SO4

79.7% by mass is H2SO4.

mass of H2SO4 = 129 g x 0.797 = 102.8 g H2SO4

moles H2SO4 = 102.8 g x 1 mol / 98.08 g = 1.0483 moles

Molar concentration = 1.0483 moles / 5.00 L = 0.210 M (3 sig. figs.)