Question

Determine the volume of Fe(NO3)3 stock solution needed to prepare a dilute solution (left side), then decide what volume of dilute solution should be prepared (right side)

Answer 1

Answer:

Here's what I get  

Explanation:

Assume you want to use 0.5 mL of a stock solution with a concentration of 0.2 mol·L⁻¹.  

You want to prepare a 0.002 mol·L⁻¹ solution.

1. Moles of Fe(NO₃)₃

$\text{Moles of Fe(NO _{3} })_{3} = \text{0.5 mL stock} \times \dfrac{\text{0.2 mmol Fe(NO _{3}) }_{3}}{\text{1 mL stock}}\\\\= \text{0.1 mmol Fe(NO _{3}) }_{3}$

2. Volume of dilute solution

$V = \text{0.1 mmoL Fe(NO _{3}) }_{3}\times \dfrac{\text{1 mL solution}}{\text{0.002 mmoL Fe(NO _{3}) }_{3}}= \textbf{50 mL solution}$