F.5 Chemistry F.5 Chemistry

Acid RainAcid Rain

Distribution of WorkDistribution of WorkName Student ID Responsibility

Kwok Wan Wan 99086250 -content-technical support

Lui Ching Lam 99243090 -editor-content

Mok Hei Man 99200420 -editor-visual design

Ng Wai Han 99242910 -information search-technical support

Soo May Kei 99200750 -information search-content

Target audience:Target audience:•F.5 chemistry students•Average ability

Purposes:Purposes:• Introduce acid rain by

lecturing •Provide Q&A section for

evaluation

WHAT IS ACID RAIN?WHAT IS ACID RAIN?

• Generally, rain water has a pH value of 5.6 because of the carbon dioxide from air dissolved in it

• Any rainfall has a pH value less than 5.6 is defined as acid rain

• When gas pollutants e.g. sulphur dioxide, nitrogen dioxide dissolve in rain water, various acids are formed.

CO2 + H2O H2CO3 (carbonic acid)SO2 + H2O H2SO3 (sulphorous acid)NO2 + H2O HNO2 (nitrous acid) +

HNO3 (nitric acid)

CAUSES OF ACID RAINCAUSES OF ACID RAINSO2 : 70% NOx : 30%

X = 1 or 2

Formation of Formation of Sulphuric AcidSulphuric Acid (H (H22SOSO44))2SO2(g) + O2(g) 2SO3(g)

SO3(g) + H2O(l) H2SO4(aq)

Formation of Formation of Nitric AcidNitric Acid (HNO (HNO33))

2NO(g) + O2(g) 2NO2(g)

4NO2(g) + 2H2O(l) + O2(g) 4HNO3(aq)

FORMATION OF FORMATION OF ACID RAINACID RAIN

SO2

NOX

1.Vegetation1.Vegetation• Wash away essential nutrients ions from s

oil• Poor growth of plants

ENVIRONMENTAL ENVIRONMENTAL PROBLEMSPROBLEMS

2.Aquatic Life2.Aquatic Life

• Inflow of acidic water containing poisonous metal ions

• Kill the fish and water plants

3. Building3. Building• Acid rain attacks the building materials

and causes corrosion.

1.What is an acid rain?

2.What is the main air pollutants for the formation of acid rain?

Question and AnswerQuestion and Answer

3.What is the pH range for the acid rain?

4.What are the major sources of air pollutants?

5.What is the side effect of acid rain on plants?

6. What is the side effect of acid rain on marine life?

7. What is the side effect of acid rain on building material?

On-line ReferencesOn-line References

• http://igc.apc.org/acidrain/

• http://beakman.com/acid/acid.html

• http://qlink.queensu.ca/~4lrm4/

Answer

1. Acid Rain is rain water with pH value less than 6. This is the rainfall with acidity level beyond what is expected in unpolluted rainfall

2. The main air pollutants are sulphur dioxide and nitrogen dioxide.

SO2 NO2

Answer

3. The unpolluted rain water is slightly acidic with pH about 5.6 because carbon dioxide in the air dissolves in rain water to form a weak acid. So, the pH of acid rain water is below 5.6.

4. The major sources were motor vehicles, factories and power stations.

5. Acid rain makes soils become acidic. When the soil becomes acidic, the plant will not grow well.

Answer

Answer

6. When acid rain runs into rivers or lakes, the pH value of water will goes down below 5. The aquatic life in water may die because of this.

Answer7. Most building materials made of lime

stone and marble. The acid rain water mainly sulphuric acid will react with calcium carbonate from limestone and marble to form calcium sulphate.

F.5 Chemistry F.5 Chemistry

Acid RainAcid Rain