Energy

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Energy
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Sample calculations During 37 minutes of
exercise, Chet burns 560 Calories. What is
Chets average power output during the
workout? 1055 Watts A bunsen burner flame burns
methane at a rate of 3 mL/s (STP). Assuming
complete combustion, what is the power of the
flame? compound ?Gf CH4 -51 kJ/mol CO2 -394
kJ/mol H2O -229 kJ/mol 107 Watts
Energy is the capacity to do work The SI Unit of
Energy is Joule (J) 4.184 J 1 calorie (cal)
1000 cal 1 food Calorie Power is the rate of
energy transfer (rate of work) The SI Unit of
Power is Watt (W) 1 W 1 J/s Ex a 100 W
lightbulb emits 100J of energy every
second Energy is neither created nor destroyed,
thus, to use energy, we need an energy source.
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Forms of Energy
http//www.eia.doe.gov/kids/energyfacts/science/fo
rmsofenergy.html
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Chemical to electrical What is the rate that
coal must be burned in order to power Biffs
vacuum cleaner? Use a value of 10 efficiency
for burning coal to actual end use electricity
(efficiency losses due to power transmission and
chemical to electrical conversion). ?Gf CO2
-394 kJ/mol 0.4 g/s 24 g/min
Electrical to mechanical Biff is vacuuming the
living room. The vacuum cleaner has a motor that
uses 12 Amps of current, and is plugged into a
standard home electrical outlet with a potential
of 110 Volts AC. What is the power consumption
of the vacuum cleaner? 1 Amp 1
Coulomb/second 1 Volt 1 Joule/Coulomb 1320
Watts
Carbon Dioxide emission Biffs vacuuming
resulted in CO2 emissions at a coal burning power
plant (also SO2 NO2, particulates, and metals
emissions result). What is the CO2 emission rate
due to Biffs vacuuming? by volume 0.75 L/s
45.0 L/min by mass 1.5 g/s 88.4 g/min
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What is Biffs average power use, and effects
(hes not vacuuming all the time). Biff is an
average person and vacuums 15 minutes each
week. 2 Watts Coal burn rate 0.6 mg / s
36.5 mg / min CO2 emission rate 1.14 mL/s
68.2 mL/min 2.2 mg / s 134 mg / min Over a
year, due to vacuuming, Biff consumes Energy
61,945,913 J 61.9 MJ Coal 18,867 g ? 42
lb CO2 (emission) volume 35,218 L mass
69,178 g ? 153 lb
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Scale up the vacuum
Vermillion, SD The average person (Biff is a
good example) may spend 15 min/week vacuuming.
What is the average rate of energy consumption
from Vermillion, SD (use pop. 10,000) due to
vacuuming? What is the rate of coal
consumption, and rate of CO2 emission? Power
consumption 19,643 Watts Coal consumption
5.98 g/s 359 g/min CO2 emission volume 11.2
L/s 670 L/min mass 21.9 g/s 1,316
g/min What is the yearly result? Energy consumed
6.19x1011 J 0.6 TJ Coal consumed
188,585,280 g ? 208 tons CO2 emission volume
352,181,242 L mass 691,784,582 g ? 762.5 tons
United States What is the average rate of energy
consumption from USA (use pop. 300,000,000) due
to vacuuming? What is the rate of coal
consumption, and rate of CO2 emission? Power
consumption 589,290 kW Coal consumption 179.5
kg/s CO2 emission volume 335,028 L/s mass
658 kg/s What is the yearly result? Energy
consumed 1.85x1016 J Coal consumed 5.66x1012
g CO2 emission volume 1.06x1013 L mass
2.08x1013 g
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The 1 mile drive
Chet is a lazy guy, and decides that he will
drive a car (mileage 25 mpg) to work every day,
even though he lives only 1 mile away, and could
walk there in 15 minutes (less worry about
finding parking or paying for parking). How much
energy is consumed in driving the car 1 mile?
How much gas (use isooctane) is consumed? How
much CO2 is released? MW 114.22 g/mol, d0.69
g/mL 2 C8H18 25 O2 ? 16 CO2 18 H2O ?Gf
kJ/mol 7.5 0 -394 -242 ?Grxn
10,675 kJ/mol Energy consumed per mile
4,882,227 J 9,764 kJ Gas consumed per mile
104.5 g CO2 emission 164 L or 322 g If Chet
works 250 days in a year, then yearly figures for
driving to work are Energy consumed
2,441,000,000 J 2.4 GJ Average power
consumption 77 W Gas consumed 52,250 g 20
gal CO2 emission 82,000 L or 161,000 g 355
lb American drivers ? 10,000 mi/yr/person
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Driving - Scaled up
Vermillion, SD The average person (Chet is a
good example) in Vermillion may commute 1 mile to
work. What is the average rate of energy
consumption from Vermillion, SD (use pop.
10,000) due to work commute? What is the rate of
gas consumption, and rate of CO2
emission? Power consumption 0.77 Megawatts
(MW) Gas consumption 16.6 g/s 994 g/min CO2
emission volume 26 L/s 1559 L/min mass 51
g/s 3,063 g/min What is the yearly
result? Energy consumed 2.44x1013 J 24 TJ Gas
consumed 200,000 gallons CO2 emission volume
819,410,400 L mass 1,609,913 kg 1,775 tons
United States If everyone in the USA (use pop.
300,000,000) drove 2 miles per day, what is the
rate of gas consumption, and rate of CO2
emission? Power consumption 23.3 Gigawatts Gas
consumption 497 kg/s CO2 emission volume
779,653 L/s mass 1,531 kg/s What is the yearly
result? Energy consumed 7.35x1017 J Gas
consumed 1.57x1010 g CO2 emission volume
2.46x1013 L mass 4.8x1010 kg
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Alternatives to Driving
Mass transit Light rail Bus Carpool Bicycles
Walking Work at home
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Stayin Alive
What is a humans average power consumption? 97
Watts Assuming 100 efficiency Human rate of
CO2 output? 4.5 mL/s 8.8 mg/s Sugar consumption
rate? 5.7 mg/s Yearly consumption Energy
3.06 GJ Sucrose 179,755 g 396 lb CO2
(emission) volume 141,912 L mass 277,517 g
612 lb
A healthy human diet is about 2000 Calories per
day. 2 C12H22O11 35 O2 ? 24 CO2 11
H2O ?Grxn -11,694 kJ/mol
Humanity consumes energy at a rate of 0.6 TW just
living
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Drying the Clothes
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