Preparation Of Ammonium Sulfate printable pdf download

Preparation Of Ammonium Sulfate

Preparation of ammonium sulfate

Student worksheet

Making ammonium sulfate

Ammonium sulfate is a complex fertiliser. This simple salt is a source of two nutrients – nitrogen

and sulfur.

About 90 percent of ammonium sulfate is produced by 3 different processes:



as a by-product from the production of caprolactam;



synthetically by reacting anhydrous ammonia and sulfuric acid;



as a by-product of coke ovens, by reacting ammonia from coke oven gas with sulfuric acid.

Ammonium sulfate can be made in the laboratory by neutralising dilute sulfuric acid with ammonia

solution.

(aq)  (NH

(aq) + 2NH

)

(aq)

Equipment and materials



Evaporating basin

Watch glass



Bunsen burner, tripod and gauze

Glass rod

−3



50 cm

measuring cylinder

1 mol dm

sulfuric acid, 25 cm



−3

Filter funnel and filter paper

2 mol dm

ammonia solution, 25 cm



Conical flask (to collect filtrate)

Full range indicator paper

Method

−3

Care: Wear eye protection. 1 mol dm

sulfuric acid is corrosive. 2 mol dm

ammonia solution is

an irritant to eyes, lungs and the respiratory system.

−3

1. Using a measuring cylinder, measure out 20 cm

of 1 mol dm

sulfuric acid into an evaporating

basin.

−3

2. Wash the measuring cylinder and then add about 25 cm

of 2 mol dm

ammonia solution to it.

Slowly add the ammonia solution to the evaporating basin, stirring the solution as you do so.

After you have added about 15 cm

check with indicator paper to see if the pH has reached 7.

Add further 1 cm

amounts of ammonia solution if necessary, checking the pH after each

addition, until the pH is 7 or above.

3. Put the evaporating basin on a tripod and gauze. Slowly evaporate the solution until it is about

one-fifth of its original volume. Caution: Do not boil the solution as it may spit.

4. Allow the concentrated solution to cool until crystals form.

5. Filter off the crystals and put the filter paper and crystals on a watch glass and dab dry with

another piece of filter paper. Cover them with a piece of clean filter paper and leave them to dry

at room temperature.

6. Label a sample tube with the name of the product, your name and the date. Weigh the labelled

sample tube and record its mass.

7. Tip your dry product into the sample tube. Weigh the tube again. Record its mass.

Preparation Of Ammonium Sulfate

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