Question

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 5.00 mL of solution B? (molar mass for oleic acid = 282 g/mol)

Answer 1

Volume$=10ml$

Solution A$=$ $3.5\times 10^{-4}\over 0.001$ $=3.5\times 10^{-7}M$

Solution B

Volume$=10ml$

$n=3.5\times 10^{-7}\times 0.2=7.0\times 10^{-8}$

Moles of Oleic acid in $5ml$ solution.

$B=7.0\times 10^{-8}\times 0.5=3.5\times 10^{-8}$

Mass of oleic acid

$3.5\times 10^{-8}\times 282=9.8\times 10^{-6}g$