Chapter 13- Nitrogen And Sulfur

Question 1

Definition of eutrophication

Answer 1

An environmental problem caused by fertilisers leached from fields into rivers and lakes. The fertilisers promote the growth of algae on the surface of water. When the algae die, bacteria thrive and use up the dissolved oxygen in the water , killing aquatic life.

Question 2

Why is N2 gas unreactive?

Answer 2

Because of its strong triple covalent bond.

Question 3

Nitrogen and oxygen form oxides in the air :

1. What provides the activation energy
2. This nitrogen (II) oxide is oxidised further by oxygen in air to give ..? Give the previous equation to get the nitrogen (II) oxide and then the oxidation reaction
3. Give the reaction of how it forms nitric acid

Answer 3

1. Lightning provides the Ea
2. N2 (g) + O2 (g) ➡ 2NO (g)
   Nitrogen (II) oxide

2NO (g) + O2 (g) ➡2NO2 (g)
Nitrogen (IV) oxide

3. Nitrogen(IV) oxide dissolves in rain water , vital part of Nitrogen cycle

2NO2 (g) + H2O (l) +1/2 O2 (g) ➡ 2HNO3 (aq)
Nitric acid

Question 4

What are essential proteins for plant growth?

Answer 4

Nitrate ions , NO3^-

Question 5

Equation for the formation of ammonium ions

Answer 5

NH3 (aq) + H^+ (aq) ➡NH4^+ (aq)

Ammonium ion

Question 6

What are the 4 common ammonium salts used in fertilisers?

Answer 6

1. Ammonium chloride, NH4Cl
2. Ammonium nitrate, NH4NO3
3. Ammonium phosphate, (NH4)3PO4
4. Ammonium sulfate, (NH4)2SO4

Question 7

Alkaline gas turns red litmus. ..

Answer 7

Blue

Question 8

Explain the 4 effects or issues of eutrophication :

Answer 8

1. Algae can spread across the surface of a water body, blocking out the light for other plant life in the water
2. When plants and algae die , bacteria in the water feed on them, decomposing the plant material
3. The bacteria multiply rapidly with so much food available, using up the dissolved oxygen in the water
4. Without oxygen the aquatic life dies

Question 9

Nitrogen oxides are pollutants because they cause 2 things :

Answer 9

1. Acid rain

2. Photochemical smog

Question 10

Nitrogen oxides also catalyse the oxidation of sulfur dioxide , SO2, in the atmosphere during formation of acid rain. What 2 reactions show the catalytic activity of Nitrogen oxides

Answer 10

SO2 (g) + NO2 (g) ➡ SO3 (g) + NO (g)

Then NO2 (g) is generated as NO reacts with oxygen in the air :

NO (g) + 1/2 O2 (g) ➡ NO2 (g)

Question 11

Car exhaust systems are fitted with catalytic converters to help reduce the pollutants from motor vehicles. The reaction on the surface of the hot catalyst e.g. platinum, reduces the nitrogen oxides to harmless nitrogen gas by the equation. …

Answer 11

2CO (g) + 2NO (g) ➡ 2CO2 (g) + N2 (g)

Question 12

When sulfuric acid is caused when it is oxidised by Nitrogen (VI) oxide, it really t’s with water to form acid rain by the equation…?

☆☆☆Fact: Sulfur dioxide is formed when we burn fossil fuels

Answer 12

SO3 (g) + H2O (l) ➡ H2SO4 (aq)

Question 13

Acid rain has harmful effects on 3 things, namely:

Answer 13

● plants (especially trees)= attacks the waxy layer and washes the nutrients out if the soil

● rivers , streams and lakes and the aquatic life in these water bodies = affects pH and aquatic life may be sensitive

● buildings, statues and metal structures =corrosion

Question 14

What are the 6 uses of nitric acid

Answer 14

1. Explosives e.g. TNT
2. Detergents
3. Paints
4. Pigments
5. Dyes
6. Nylon

Question 15

What are 6 uses of sulfuric acid ?

Answer 15

1. Manufacturing fertilisers
2. Detergents
3. Paints

4 pigments

5. Dyes
6. Synthetic fibres