Question

Please help! Calculate the percent by mass of water in FeCl2 · 4H20.

Answer 1

Answer:

36.23 %

Explanation:

Let's assume we have 1 mol of FeCl₂ · 4H₂O. In that case we would have:

• 1 mol of FeCl₂, weighing 126.75 g (that's the molar mass of FeCl₂), and

• 4 moles of H₂O, weighing (4 * 18 g/mol) 72 g.

Now we can calculate the percent by mass of water:

• % mass = mass of water / total mass * 100%

• % mass = $\frac{72}{72+126.75}$ * 100% = 36.23 %