Chem 106 Practical Everyday Chemistry ENERGY Dr. Ron Rusay Diablo Valley College Spring 2003

Chem 106Chem 106 Practical Everyday Chemistry Practical Everyday Chemistry

ENERGYENERGY

Dr. Ron Rusay Dr. Ron Rusay Diablo Valley College Diablo Valley College

Spring 2003Spring 2003

EnergyEnergy

Energy can be defined as the Energy can be defined as the capacity to do work. capacity to do work.

Can you name other types of Can you name other types of energy?energy?

Chemical Energy is defined as Chemical Energy is defined as heatheat..

Temperature v. EnergyTemperature v. Energy

TemperatureTemperature reflects reflects random motions random motions of particles; i.e. the kinetic energy of a of particles; i.e. the kinetic energy of a system.system.

HeatHeat involves a involves a transfer of energy transfer of energy betweenbetween 2 objects due to different energies 2 objects due to different energies and temperature differences. and temperature differences. Always: HOT -Always: HOT -> > coldcold

Heat TransferHeat Transfer

Have you ever burned the roof of your Have you ever burned the roof of your mouth?mouth?

QuickTime™ and aIntel Indeo® Video R3.2 decompressor

are needed to see this picture.

Heat CapacitiesHeat Capacities

SubstanceSpecific HeatJ / oC . gH2O (l) 4.18H2O (s) 2.03Al (s) 0.89Fe (s) 0.45

Greenhouse GasesGreenhouse Gases

What is a greenhouse gas?The sun’s energy & the molecule’s shape decide.

•Our atmosphere (air) is 78% nitrogen and 21% oxygen. Our atmosphere (air) is 78% nitrogen and 21% oxygen. •Neither are greenhouse gases. They do not absorb infrared radiation (heat). Neither are greenhouse gases. They do not absorb infrared radiation (heat). •However, HHowever, H22O and COO and CO2 2 can absorb infrared energy. Without them earth would can absorb infrared energy. Without them earth would

be very chilly.be very chilly.

http://zebu.uoregon.edu/1998/es202/l13.htmlhttp://zebu.uoregon.edu/1998/es202/l13.html

http://chemistry.http://chemistry.beloitbeloit..eduedu/Stars//Stars/EMSpectrumEMSpectrum/index.html/index.html

What does a molecule’s shape have to do with heat absorbance?What does a molecule’s shape have to do with heat absorbance?…How can and a TV remote be used to show the difference?…How can and a TV remote be used to show the difference?

QuickTime™ and aGIF decompressor

are needed to see this picture.

Infrared AbsorbanceInfrared Absorbance

RemoteTV

Infrared AbsorbanceInfrared Absorbance

Sample

TV Remote

Infrared Absorbance & Molecular Vibrations Infrared Absorbance & Molecular Vibrations Stretching & BendingStretching & Bending

QuickTime™ and aAnimation decompressor

are needed to see this picture.

Infrared Absorbances: Molecular Shapes & Vibrations Infrared Absorbances: Molecular Shapes & Vibrations

Stretching & Bending in WaterStretching & Bending in Water

Antisymmetric Stretching

Bending

Symmetric Stretching

http://ep.llnl.gov/msds/Chem120/atmos-gases.html

QuickTime™ and aGIF decompressor

are needed to see this picture.

QuickTime™ and aGIF decompressor

are needed to see this picture.

QuickTime™ and aGIF decompressor

are needed to see this picture.

Molecules & Science are NOT passive!Molecules & Science are NOT passive!

QuickTime™ and aGIF decompressor

are needed to see this picture.

QuickTime™ and aGIF decompressor

are needed to see this picture.

QuickTime™ and aGIF decompressor

are needed to see this picture.

Measuring Infrared AbsorbanceMeasuring Infrared Absorbance An Infrared SpectrophotomerAn Infrared Spectrophotomer

Infrared Spectra: http://chemistry.beloit.edu/Warming/pages/infrared.html

QuickTime™ and aGraphics decompressor

are needed to see this picture.

Nitrogen & Oxygen produce flat lines: 100% Transmission, 0 Absorbance

Combustion Combustion Energy = Carbon Energy = Carbonhttp://chemistry.beloit.edu/Warming/pages/emissions.html

QuickTime™ and aGraphics decompressor

are needed to see this picture.

Why has COWhy has CO2 2 been increasing? been increasing?

2 C8H18(l)+ 25 O2(g)-----> 16 CO2(g)+18 H2O(l)

QuickTime™ and aGIF decompressor

are needed to see this picture.

Combustion of Octane:

+ + HEAT HEAT

Using the Energy fromUsing the Energy fromBurning GasolineBurning Gasoline

Human factors: Human factors: Atmospheric Changes in COAtmospheric Changes in CO22

Correlating Mauna Loa, Hawaii with 8 other global sites

Direct atmospheric CO2 measurements and reconstructions from measurements of air bubbles trapped in ice.

QuickTime™ and aGraphics decompressor

are needed to see this picture.

http://chemistry.http://chemistry.beloitbeloit..eduedu/Warming/movies/CO2./Warming/movies/CO2.movmov

Human factors: Human factors: Atmospheric Changes in COAtmospheric Changes in CO22 and Temperature and Temperature

Tem

per

atu

re

CO

2 c

on

cen

trat

ion

Heats of CombustionHeats of Combustion

Combustion of octane releases 5,470 kJ per Combustion of octane releases 5,470 kJ per mole of octanemole of octane ((HHcombcomb = -5,470 kJ/mol) = -5,470 kJ/mol)

How many pounds of COHow many pounds of CO22 are added to are added to

atmosphere from burning 1 gallon of atmosphere from burning 1 gallon of gasoline?gasoline?

2 C8H18(l)+ 25 O2(g)-----> 16 CO2(g)+18 H2O(l)

QuickTime™ and aGIF decompressor

are needed to see this picture.

1 Gallon Octane ~ 2.6 kg (~ ? lbs)

+~ 9.2 kg Oxygen

(~ 20 lbs)

~8.1 kg COCO22

(~18 lbs)+

~ 3.7 kg Water (H2O) (~8 lbs)

Combustion of Octane:

+ + HEAT HEAT

What can be done to reduce the rate of What can be done to reduce the rate of increase of COincrease of CO22??

•What do you drive?

http://www.eren.doe.gov/feguide

http://www.epa.gov/oms/17-tips.htm

What can be done to reduce the rate of What can be done to reduce the rate of increase of COincrease of CO22??

•Cutting back on driving?

•How many pounds of CO2 do you produce each year from driving?

•Estimated driving miles / week? ____ mi/weekYour vehicle’s gas mileage___ mi/gal (national avg = 25

mi/gal) 18 lbs/gal x 52 weeks/yr x ___ mi/week ÷ ___ mi/gal = ____

lbs CO2 http://www.eren.doe.gov/feguide

http://www.epa.gov/oms/17-tips.htm

What can be done to reduce the rate of What can be done to reduce the rate of increase of COincrease of CO22??

•Estimated driving miles / week? _200_ mi/weekVehicle’s gas mileage_25_ mi/gal (national avg)

18 lbs/gal x 52 weeks/yr x _200_ mi/week ÷ _25 _ mi/gal = _7488_ lbs

•About 3.5 tons of COAbout 3.5 tons of CO2 2 per student per year!per student per year!

• 75% of the electricity generated in California comes from burning carbon fuels.

•When finished turn off lights & electrical devices…..

Including Computers!Including Computers!

http://www.epa.gov/oms/17-tips.htm

The average miles driven per week by a DVC student is about 200 mi/week.

Does Oil play a role in public policy?Does Oil play a role in public policy?