# How many grams of KI must be dissolved in 250.0 mL of solution to form a 0.075 M solution?

May 28, 2016

Approx. $3 \cdot g$

#### Explanation:

$\text{Concentration "="Moles"/"Volume}$

Here we are given the volume and the concentration and can thus find the molar quantity, and from this we find the mass of $K I$.

$\text{Moles } = 0.075 \cdot m o l \cdot \cancel{{L}^{-} 1} \times 250.0 \times {10}^{-} 3 \cancel{L}$
$=$ $1.875 \times {10}^{-} 3 \cdot m o l$.

$\text{Mass}$ $=$ $\text{moles"xx"molar mass}$

$=$ $1.875 \times {10}^{-} 3 \cdot \cancel{m o l} \times 166.0 \cdot g \cdot \cancel{m o {l}^{-} 1}$ $\cong 3 \cdot g$