# What is the molarity if you dissolve 15 g of FeCl_3 to make up 250 mL solution?

Mar 7, 2016

0.37 M

#### Explanation:

First calculate the molar mass of $F e C {l}_{3}$:

$55.85 + 3 \cdot 35.45 = 162.20 g / m o l$

Then calculate how many moles are 15 g of $F e C {l}_{3}$:

color(red)(n=m/M

$n = \frac{15}{162.20} = 0.0925 m o l$

Then calculate the concentration:

color(red)(c=n/v

$n = 0.0925 m o l / 0.250 L = 0.37 m o l / L \left(\mathmr{and} 0.37 M\right)$

The concentration is given with two representative digits which are the same ones of 15 grams.