SC15

Question 1

What are fertilisers?

Answer 1

Fertilisers are soluble compounds added to soil to replace minerals used up by plants. They are important in promoting plant growth and can be natural or artificial.

Question 2

What do fertilisers provide and why?

Answer 2

They provide nitrogen, phosphorus and potassium as soluble compounds since root hair cells only absorb mineral ions that are dissolved in water.

Question 3

Using what are artificial nitrogenous fertilisers made?

Answer 3

They are made using ammonia as the raw material.

Question 4

What are two nitrogenous fertilisers?

Answer 4

1. Ammonium nitrate
2. Ammonium sulfate

Question 5

What is the word and chemical equation for ammonium nitrate?

Answer 5

Word equation: ammonia + nitric acid –> ammonium nitrate
Chemical equation: NH₃ + HNO₃ –> NH₄NO₃

Check chem booklet p7 slide 40.

Question 6

What is the word and chemical equation for ammonium sulfate?

Answer 6

Word equation: ammonia + sulfuric acid –> ammonium sulfate
Chemical equation: 2NH₃ + H₂SO₄ –> (NH₄)₂SO₄

Check chem booklet p7 slide 40.

Question 7

What are some factors taken into account to choose a reaction pathway?

Answer 7

1. Availability and cost of raw materials and energy supplies
2. The rate of reaction and the equilibrium position
3. Atom economy, yield and usefulness of by-products