1.00 mL of a 3.50 *10^-⁴ M solution of oleic acid is diluted with 9.00 mL of petroleum ether, forming solution A. 2.00 mL of solution A is diluted with 8.00 mL of petroleum ether, forming solution B. How many grams of oleic acid are in 5.00 mL of solution B? (molar mass for oleic acid = 282 g/mol)

Question

Quizplus · Accepted Answer

The concentration of solution A is 3.50 x 10^-5 M. Solution B is diluted from solution A by a factor of 5, so its concentration is 7.00 x 10^-6 M. In 5.00 mL of solution B, the moles of oleic acid are (7.00 x 10^-6 mol/L) x (5.00 x 10^-3 L) = 3.50 x 10^-8 mol. The mass is (3.50 x 10^-8 mol) x (282 g/mol) = 9.87 x 10^-6 g.

100 ML of a 3