7th Chemistry - Acid Rain

St. George's College

Subject: 7th CHEMISTRY

Class: Acid Rain Date: November 9th

Teacher's notes

Objectives

Vocabulary Link and Learn

In‐Class Survey

Prepared by

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7th Beethoven ‐ Acid Rain Name

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Name

Ariana

Luis

Gabriel

Andrea

Andrea

Sebastián

Abraham

Ivanna

Giacomo

Camila

Fabiana

Carlos

Sinead

Aarón

Liliam

Paola

Francesca

Enrique

Rodrigo C.

Alessandra

Andres

Irma

Stefano

Sophia

Jean Pierre

Naomi

Diego

Kiara

Rodrigo H.

Christopher

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7th Mozart ‐ Acid Rain Name

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Name

Nicole

Roberto M.

Luis

Giancarlo

Luciana

Fiorella

Antonella

Gabriela

Valeria Ch.

Steffano

Valeria C.

Javier

Sylvana

Roberto R.

Analucía

Diego

Camila

Luis Fernando

Franco

Sebastián

Ramiro

Julio

Sara

Sherley

Alicia

César

José Luis

Vilma

Sergio

Alessandra V.

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New knowledge beginning......

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ACID RAIN

pH

Rain from an unpolluted atmosphere has a pH close to 6.0 (slightly acidic).

This acidity is due to the reaction of water vapour and non‐metal oxides in the atmosphere, such as carbon dioxide and nitrogen oxide, forming dilute acids.

• Carbon dioxide reacts with water to form carbonic acid: CO2(g) + H2O(l) H2CO3(aq) Since carbonic acid is a weak acid it partially dissociates: CO2(g) + H2O(l) H+(aq) + HCO3‐(aq) • Nitrogen dioxide reacts with water to form a mixture of nitrous acid and nitric acid: 2NO2(g) + H2O(l) HNO2(aq) + HNO3(aq)

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ACID RAIN

pH

Acid rain has a pH below 5.6 due mainly to the reaction of water vapour with sulfur dioxide and the oxides of nitrogen.

Sulfur dioxide reacts with water to form sulfurous • acid (H2SO3): SO2(g) + H2O(l) H2SO3(aq) Sulfur dioxide (SO2) can be oxidised gradually to sulfur trioxide (SO3): 2SO2(g) + O2(g) ‐‐‐‐‐> 2SO3(g) Sulfur trioxide (SO3) reacts with water to form sulfuric acid (H2SO4): SO3(g) + H2O(l) ‐‐‐‐‐> H2SO4(aq) • Oxides of nitrogen, particularly nitrogen dioxide (NO2) react with water to form nitrous acid (HNO2) and nitric acid (HNO3): 2NO2(g) + H2O(l) ‐‐‐‐‐> HNO2(aq) + HNO3(aq) 7

Combustion of Fuels

ACID RAIN Acid Carbonic acid (H2CO3)

Clean air Natural carbon dioxide (CO2) produced during plant and animal respirationproduced during decomposition of organic matter.

Polluted air Carbon dioxide (CO2) released from the combustion of fuels.

The complete combustion of coal: C(s) + O2(g) ‐‐‐> CO2(g) The complete combustion of petrol, for example octane C8H18(l)): 2C8H18(l)+25O2(g)‐‐‐>16CO2(g)+18H2O(g) Complete combustion of ethanol (ethyl alcohol): C2H5OH(l)+3O2(g)‐‐‐>2CO2(g)+3H2O(g)

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Objectives • Study the chemical composition of the air and discuss the ideal of air quality in relation to the idea of human and environmental health.

• Discuss the idea of air pollutant and study some of them.

Note: All, or most, of the objectives will be covered during class time, however the student must be responsible for those objectives not covered or concluded.

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Vocabulary • • • • •

Air Pollution Acid Rain Fumes Hazard

Note: Most of the vocabulary words will be covered during class time, however the student must be responsible for those words not covered or concluded.

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Link and Learn You can visit the following websites to improve your understanding on the present topic: • • • • • •

www.eea.europa.eu/ www.epa.gov www.breathingearth.net/ http://science‐learning2009.wikispaces.com http://learningandscience.blogspot.com http://libraryatstgeorge.blogspot.com

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Prepared by

Gerardo LAZARO Science Lead Teacher Email: glazaro@sanjorge.edu.pe Wiki: http://science‐learning2009.wikispaces.com Blog: http://learningandscience.blogspot.com Twitter: http://twitter.com/glazaro

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