Synthesis of Iron (II) hydroxide

Group members: Class: ___________

1. _________________________________

2. _________________________________

3. _________________________________

4. _________________________________

5. _________________________________

6. _________________________________

Method – Read step 4 carefully

1. Place a 100ml beaker on the balance and press tare (T).

2. Accurately weigh 6.2g of iron powder into the

beaker. Using a marker pen label your beaker.

3. Using a 250ml measuring cylinder, dispense 120ml of 1M hydrochloric acid (HCl). Add to a 600ml

beaker. DO NOT ADD THE IRON POWDER.

4. Place the 600ml beaker on a hot plate inside the fume hood, add the iron powder and boil the

solution. Hydrogen gas will be produced; the reaction is complete when no more gas is being

produced. This will take about 20 minutes. When the solution volume drops to half of its original

value, add water to restore the original volume.

5. Once the reaction is complete remove the beaker from the

hotplate and allow it to cool inside the fume hood.

6. Once the solution has reached room temperature filter the

solution to remove any unreacted iron. Keep the filtrate (the

solution), ensuring the glassware has been labelled.

7. Whilst wearing gloves, add 50ml of 2.5M sodium hydroxide (NaOH) to the filtrate. A precipitate

will form (Fe(OH)2). Stir the solution with a glass rod and let the solution stand for a few minutes to

ensure the reaction is complete.

8. Filter the solution, this time you want to collect the solid and discard of the filtrate.

9. Using tweezers, carefully remove the filter paper from the funnel and place it on a labelled watch-

glass.

10. Place the watch-glass inside the incubator for 5 minutes (or until dry). Ensuring you keep an eye

on your sample to prevent the filter paper burning and contaminating your sample.

11. Once dry, weigh the Fe(OH)2 on the filter paper. Subtract the mass of a filter paper to find the

mass of your sample.

Analysis

Mass of 10 filter papers

Grams Fe(OH)2 = ____________

Fe(s) + 2HCl(aq) → FeCl2(aq) + H2(g)

Number of moles (n) = concentration(M) x volume(L) (Use for HCl and NaOH).

Number of moles (n) = Mass (g) / molar mass (g/mol)

Determine the limiting reagent:

How many grams of FeCl2 can be produced?

FeCl2(aq) + 2NaOH(aq) → Fe(OH)2(s) + 2NaCl(aq)

Determine the limiting reagent:

How many grams of Fe(OH)2 can be produced? (theoretical yield)

55.845g/mol 36.46g/mol 126.75g/mol 2.02g/mol

126.75g/mol 39.997g/mol 89.86g/mol 58.44/mol

Determine the percentage yield using the number of grams of Fe(OH)2 your group produced (actual yield) and the theoretical yield calculated above.