Sodium hydroxide solution was added to 200 g of a 5% solution of iron (III) chloride.

Sodium hydroxide solution was added to 200 g of a 5% solution of iron (III) chloride. Calculate the mass of the precipitate formed.

Given:

m (FeCl3) = 200 g

w% (FeCl3) = 5%

To find:

m (draft) -?

Decision:

FeCl3 + 3NaOH = Fe (OH) 3 + 3NaCl, – we solve the problem based on the composed reaction equation:

1) Find the mass of ferric chloride in solution:

m (FeCl3) = 200 g * 0.05 = 10 g

2) Find the amount of ferric chloride:

n (FeCl3) = m: M = 10 g: 162.5 g / mol = 0.06 mol

3) We make a logical equation:

if 1 mol of FeCl3 gives 1 mol of Fe (OH) 3,

then 0.06 mol FeCl3 will give x mol Fe (OH) 3,

then x = 0.06 mol.

4) Find the mass of precipitated iron hydroxide:

m (Fe (OH) 3) = n * M = 0.06 mol * 107 g / mol = 6.42 g.

Answer: m (Fe (OH) 3) = 6.42 g.