Earth as a Closed System The Earths Atmosphere

Earth as a Closed System

The Earth’s Atmosphere ‘The Precious Envelope’ • • • 78% Nitrogen 20% Oxygen 1% Argon 0. 03% CO 2 Trace Elements Nitrogen Oxygen Helium Neon Water vapor Air Carbon dioxide Argon

The Earth’s Atmosphere From Space Component Percent composition Nitrogen, N 2 Oxygen, O 2 Argon, Ar Water, H 2 O Carbon dioxide, CO 2 78% 21% 0. 9% 0 – 4% (variable) 0. 034% (variable) Copyright © 2007 Pearson Benjamin Cummings. All rights reserved.

Light from the sun Reflected heat lost to outer space Reflected heat absorbed by atmosphere Global Warming Kelter, Carr, Scott, Chemistry A Wolrd of Choices 1999, page 392

The Greenhouse Effect HIGH ENERGY, SHORT l LIGHT PASSES EASILY THROUGH ATMOSPHERE CO 2 MOLECULES LOWER ENERGY, LONGER l LIGHT IS BLOCKED BY CO 2 AND CH 4; ENERGY DOESN’T ESCAPE INTO SPACE; ATMOSPHERE HEATS UP ENERGY RELEASED AS HEAT

Greenhouse Gases

The Earths Atmosphere Ozone Zumdahl, De. Coste, World of Chemistry 2002, page 309

Carbon Dioxide Levels Atmospheric CO 2 (ppm) 350 300 250 1000 1500 Year Zumdahl, De. Coste, World of Chemistry 2002, page 310 2000

(a) Records from Antarctic ice cores (1006 -1969 A. D. ) Copyright © 2007 Pearson Benjamin Cummings. All rights reserved. (b) Records from monthly air samples, Mauna Loa Observatory, Hawaii (1958 -2002)

Why more CO 2 in atmosphere now than 500 years ago? burning of fossil fuels -- coal -- petroleum -- natural gas -- wood deforestation -- urban sprawl -- rain forests -- wildlife areas * The burning of ethanol won’t slow greenhouse effect. C 2 H 5 OH + O 2 CO 2 + H 2 O

Greenhouse Effect Atmospheric CO 2 (ppm) 350 300 250 1000 1500 Year • FACT: 15% increase in [CO 2] in last 100 years • Cause: – – Change from agricultural to industrial lifestyle Burning of fossil fuels (petroleum, coal) Increase CO 2 emissions (cars, factories etc…) Deforestation • Effects: – Global warming – Melt polar ice caps flooding at sea level – Warming oceans more powerful storms 2000

Greenhouse Effect Children and pets left unattended in vehicles with windows rolled up can die from high temperature in vehicle. Carbon dioxide in atmosphere traps heat and acts like a glass cover holding in the heat on planet Earth.

What can we do? 1. Reduce consumption of fossil fuels. At home: insulate home; run dishwasher full; avoid temp. extremes (A/C & furnace); wash clothes on “warm, ” not “hot” mow lawn less often (small engines) On the road: bike instead of drive; carpool; energy-efficient vehicles 2. Support environmental organizations. 3. Rely on alternate energy sources. solar, wind energy, hydroelectric power

Sources of Energy