Question

How many mL of a 0.230 M aqueous solution of cobalt (II) chloride, CoCl2, must be taken to obtain 4.66 grams of salt?

Answer 1

Answer:

$\large \boxed{\text{156 mL}}$

Explanation:

1. Calculate the moles of CoCl₂

$\text{Moles of CoCl}_{2} = \text{4.66 g CoCl}_{2} \times \dfrac{\text{1 mol CoCl}_{2}}{\text{129.84 g CoCl}_{2}} = \text{0.035 89 mol CoCl}_{2}$

2. Calculate the volume of solution

$c = \dfrac{\text{moles }}{\text{litres}}\\\\\text{litres} = \dfrac{\text{moles}}{c} = \dfrac{\text{0.035 89 mol}}{\frac{\text{0.230 mol}}{\text{1 L}}} = \text{0.156 L} = \text{156 mL}\\\\\text{You need \large \boxed{\textbf{156 mL}} of solution}$