Question

What is the molarity of a solution made by dissolving 5.5 g of KI in enough water to make 150 ml of solution?

Answer 1

Answer:

Explanation:

molarity is moles of solute/L solution

5.5 g                         1 moles Kl             1000 mL

_____                   *  __________    *    ________ = 0.22088 M

150 ml of solution     166 grams              1 L

       (39 grams K+ 127 grams I) ^

Answer 2

Answer:

$\boxed{\text{0.22 mol/L}}$

Explanation:

$\text{Molar concentration} = \dfrac{\text{moles}}{\text{litres}}\\\\\text{c} = \dfrac{n}{V}$

1. Convert grams to moles.  

$\text{Moles KI = 5.5 g KI} \times \dfrac{\text{1 mol KI}}{\text{166.0 g KI}} = \text{0.0331 mol KI}$

2. Convert millilitres to litres  

$\text{V = 150 mL} \times \dfrac{\text{1 L}}{\text{1000 mL}} = \text{0.1500 L}$

3. Calculate the molar concentration

$c = \dfrac{\text{0.0331 mol}}{\text{0.1500 L}} = \text{0.22 mol/L}$

The molar concentration of KI is $\boxed{\textbf{0.22 mol/L}}$.