C15.7 Making fertilisers in the lab

Question 1

How is the ammonia used?

Answer 1

Can be used as a fertiliser itself in liquid form

Most is changed into compounds of ammonia

Question 2

How is ammonium nitrate made?

Answer 2

10% of ammonia made in the Haber process is converted in another process into nitric acid
Then ammonia and nitric acid reacts to make ammonium nitrate

Question 3

When are salts formed?

Answer 3

When acids and alkalis react together in a neutralisation reaciton

Question 4

How can you make ammonium sulfate in the lab?

Answer 4

By using the titration of dilute sulfuric acid against ammonia solution

Question 5

How can you set-up the titration to make ammonium sulfate?

Answer 5

Measure 25cm^3 of ammonia with a pipette and put it into a conical flask
Add dilute sulfuric acid 1cm^3 at a time using a burette
Stir the flask and dip a glass rod
Then test a drop of the solution on blue litmus paper
Keep adding until it turns pink

Question 6

Why is important to repeat the titration?

Answer 6

Repeat until you get 2 volumes of sulfuric acid with 0.1cm^3 of each other - these are called concordant results

Question 7

What do you do after you have collected the solution?

Answer 7

Put it on an evaporating dish and heat until half the solution has evaporated
Leave the rest of the solution to dry to leave crystals of ammonium sulfate