Energy: Hard Work

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(No Transcript)
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Energy Hard Work Hot Stuff

• Energy is the ability to do work.
• Work is done when movement occurs against a
  restraining force, and it is equal to the force
  multiplied by the distance over which the motion
  occurs.
• Heat is that which flows from a warmer to a
  cooler substance
• Temperature is a property that determines the
  direction of heat flow. When two bodies are in
  contact, heat always flows from the object with a
  higher temperature to the one with lower
  temperature.

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Energy Hard Work Hot Stuff

• Heat is a consequence of motion at the molecular
  level. When matter, for example liquid water in a
  pan, absorbs heat, its molecules move more
  rapidly.
• Temperature is a statistical measure of the
  average speed of that motion. Hence, temperature
  rises as the amount of heat energy is a body
  increases.

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Energy Hard Work Hot Stuff

• Units of energy are termed the Joule (J).
• Calories are also used as a measure of energy.
• 1cal 4.184J
• 1Cal 1kcal 1000 cal
• 1Cal 4184J

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Your Turn

• Convert the 425 kcal released when a donut is
  metabolized to joules. Then calculate the number
  of books you could lift to a shelf 6 feet off the
  floor with that amount of energy. (It takes 1J of
  energy to lift a book 4 inches.)

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Your Turn

• A 12 oz can of a soft drink has an energy
  equivalent of 92kcal. Assume that you use this
  energy to lift concrete blocks that weigh 22lb
  (10kg) each. How many of these blocks could you
  lift to a height of 4 feet with this quantity of
  energy? (It takes 10J of energy to lift a book 4
  inches.)

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Energy Conservation and Consumption

• Strictly speaking, energy is not consumed.
• Law of Conservation of Energy or the First Law of
  Thermodynamics assures us of this.
• The energy in the universe is constant.
• However, energy sources like coal, oil, natural
  gas are consumed.
• The U.S. and Canada use more fossil fuel than any
  nation at 95 million kcal.

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Energy Conservation and Consumption

• Graphs like on ICT show that the worlds reliance
  and usage of fossil fuel is growing
  exponentially.
• We are using 5 times as much fossil fuels in 2000
  than we did in the 1950s.
• Our main sources of energy are oil, natural gas,
  coal, nuclear power and hydropower, geothermal,
  wind and solar power in that order.

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Consider This

• Imagine that you are put in a time machine and
  transported 200 years into the future. You become
  an instant celebrity. The talk show host of the
  day invites you in to be interviewed. The first
  question is How could the people of your century
  feel justified in using up so much of the worlds
  store of non-renewable resources such as oil and
  coal? What is your answer?

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Zero Talking on this Activity

• Get in groups of 32 min
• Give your essay to the person to the right for
  them to read10 sec
• Read the article that you now have and respond to
  them in another short paragraph2 min
• Pass your paper to the right again10 sec
• Read the article and the response and write a
  response of your own commenting on the original
  and the response2 min
• Give the paper back to the original author2 min
• Read the responses to your essay2 min
• Discuss your papers and responses with each
  other2 min

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Energy Where from and How Much?

• At a time when the nation is seeking new sources
  of energy, it is reasonable to ask what is it
  that makes some substances such as coal, oil or
  wood usable as fuels, while many others are not.
• To find the answer, we must consider the
  properties of fuels and the means by which energy
  is released from them.

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Energy Where from and How Much?

• The most common energy-generating chemical
  reaction is burning or combustion.
• Combustion is the combination of the fuel with
  oxygen to form CO2, H2O and energy.
• The stored energy (potential energy) of the
  reactants is more than the stored energy of the
  products, so the 1st Law of Thermodynamics tells
  us that energy must be given off (usually as
  heat).

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Energy Where from and How Much?
CH4 O2 ? CO2 H2O Energy

• The above reaction is exothermic.
• This means that energy was given off as the
  reactants broke bonds and reformed bonds to make
  products.
• Endothermic reactions are those that need energy
  to be added to the reactants in order to turn
  into products.

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Energy Where from and How Much?

• The amount of heat energy produced by a reaction
  such as the previous can be calculated using a
  calorimeter.
• The amount of heat generated depends on the
  amount of fuel burned.
• Heat of combustion is the quantity of heat energy
  evolved when a specified amount of a substance
  burns in oxygen. (kJ/mole or equivalents)

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Energy Where from and How Much?

• If the heat of combustion of methane is
  determined by calorimetry to be 802 kJ/mole, it
  means that every mole of methane emits 802kJ of
  energy.
• We can use factor label to determine that the
  amount of energy given off per gram is 52kJ/g.
• The fact that heat is evolved signals that there
  is a decrease in the energy of the chemical
  system during the reaction.

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Energy Where from and How Much?

• The fact that heat is evolved signals that there
  is a decrease in the energy of the chemical
  system during the reaction.
• So, the energy change is reported as
  -802kJ/mole.

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Energy Where from and How Much?

• But where does the energy come from? We have
  discussed that energy is released during a
  reaction such as this, and that the reactants
  have more energy than the products, but where
  does the energy come form?
• The answer is found in the molecular structures
  of the compounds

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Today

• Pick up more notes at desk nearest door.
• WHAT!? MORE NOTES?!
• Yes, more notes
• Get out a sheet of paper, periodic table,
  pen/pencil, and a calculator for the graded quiz.
  
• QUIZ?!
• Yes, a graded quiz.
• GRADED QUIZ?! THIS STINKS!Yes, I know.

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Todays Graded Quiz CheckAbsolutely no talking
or asking questionsif you are talking you will
get no credit for this graded quiz.

• Define electronegativity (?).
• Which has a higher ?,
• Ba or O
• Cl or F
• N or C
• Draw NF3 and check the formal charges.
• List two units to measure heat.
• What does it mean to say the heat of combustion
  of methane is -802kJ/mol?

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Final Quiz Question

• According to the information given to you, the
  heat of combustion of methane is 802kJ/mole.
  Methane is usually sold by the standard cubic
  foot (SCF). One SCF contains 1.25moles of CH4.
  Calculate the energy (in kJ) that would be
  released by burning 15 SCF of methane. (Hint
  this is a factor label problem)

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Energy Where from and How Much?
Write the balanced equation for the combustion of
methane (CH4).
Draw all the molecules from this equation.
O
H
H
H
C
H
H
OO

OCO
?

OO
O
H
H
H

• Bond breaking is endothermicneed energy to tear
  away atoms.
• Bond forming is exothermic.

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Energy Where from and How Much?
O
H
H
H
C
H
H
OO

OCO
?

OO
O
H
H
H

• For this reaction to take place, 4 C-H bonds and
  2 OO bonds are broken and 2 CO and 4 O-H bonds
  are formed.

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Calculating Energy Changes in Chemical Reactions

• Bond energy is the amount of energy that must be
  absorbed to break a specific chemical bond.
• The more bonds broken, the more energy it takes.
• All values in the table are given in kJ/mole and
  are given a positive sign.
• Energy used to break bonds is given () and
  energy given off is given (-).

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Calculating Energy Changes in Chemical Reactions

• Breaking Bonds (endo)
• 4 C-H bonds 411kJ 1644kJ
• 2 OO bonds 494kJ 988kJ
• Total energy absorbed 2632kJ
• Making Bonds (exo)
• 2 CO bonds -799kJ -1598kJ
• 4 H-O bonds -459kJ -1836kJ
• Total energy released -3434kJ
• Net energy -802kJ (released)

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More Funner Way

• ?Hºrxn (S bonds broken) (S bonds formed)

Sum of
Heat of the reaction at standard conditions
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You Try

• Determine the heat of combustion of one mole of
  propane (C3H8).
• Acetone (H3CCOCH3) can be converted to isopropyl
  alcohol (H3CHCOHCH3) by reacting it with H2 gas.
  Calculate the heat change of this reaction.
• Oxygen difluoride reacts with water to form
  oxygen and hydrofluoric acid. If the ?Hºrxn is
  -318kJ/mole, what is the bond dissociation energy
  associated with an OF bond?
• How much energy is given off when 150mL of
  ethanol (C2H5OH) is burned on a desk? (Density
  0.85g/mL)

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You Try

• How much energy is given off when 100g of methane
  reacts with oxygen?

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Hesss Law

• Hess noticed that heat change was a state
  functionwhich means
• That it doesnt matter the path you take to get
  to the end as long as you get to the end.
• A state function is like going to the baseball
  field.
• There are many paths that you can take to get to
  the fieldbut the displacement of your body from
  this spot to the field is the same.

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Hesss Law
BB Field
U
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Hesss Law

• In all cases, you ended up about 500 feet from
  where you started.
• Hess didnt care about the path you took as long
  as you ended up in the same place.
• He took this idea into the chemistry world.
• He stated in going from a particular set of
  reactants to a particular set of products, the
  change in enthalpy (H) is the same whether the
  reaction took place in one step or a series of
  steps.

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Hesss Law

• N2(g) 2O2(g)? 2NO2(g) ?H1 68kJ
• This shows the reaction in one step.
• But the reaction can be thought of as occurring
  in 2 distinct steps
• N2(g) O2(g) ? 2NO(g) ?H2 180kJ
• 2NO(g) O2(g) ? 2NO2(g) ?H3 -112kJ
• N2(g) 2O2(g)? 2NO2(g) ?H1 68kJ

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Hesss Law

• Often we will know the ?H of a reaction or we can
  use calorimetry to get it.
• But sometimes we are unable to use any means to
  calculate itother than Hesss Law.

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Hesss Law

• For example it is too difficult to use
  calorimetry to calculate ?H of diborane (B2H6).
  So we use Hesss Law and some reactions that we
  can determine ?H for.
• 2B (s) 3H2 (g) ? B2H6 (g)
• We then use the following data
• 2B (s) 3/2O2 (g) ? B2O3 (s) ?H -1273kJ
• B2H6 (g) 3O2 (g) ? B2O3 (s) 3H2O (g) ?H
  -2035kJ
• H2 (g) ½ O2 (g) ? H2O (l) ?H -286kJ
• H2O (l) ? H2O (g) ?H 44kJ

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All you!

• Given the following data
• 2O3 (g) ? 3O2 (g) ?H -427kJ
• O2 (g) ? 2O(g) ?H 495kJ
• NO(g) O3(g) ? NO2(g) O2 (g) ?H -199kJ
• Calculate H for this reaction
• NO(g) O(g) ? NO2(g)

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Getting a Reaction Started Activation Energy

• CH4 O2 ? CO2 H2O energy
• What happens when gas like methane is pumped into
  a room with oxygen?
• Nothing.
• Just because 2 chemicals are in contact with each
  other does not mean that a reaction will occur
  even if it is exothermic.
• A spark or a flame is needed to start the
  reaction and get the methane to burn in oxygen.

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Getting a Reaction Started Activation Energy

• The spark or flame supplies the energy needed to
  jumpstart the reactioncalled activation energy.

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Energy
Activation Energy
Energy of Reactants
-?H
Energy of Products
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Getting a Reaction Started Activation Energy

• The bigger the hill, the slower or less likely
  the reaction will take place.
• The lower the hill, the faster the reaction will
  take place.
• Some possible fuels have too high of Ea and are
  not useful and some have to low of a Ea and are
  dangerous.

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Other Ways to get a Reaction to Go!

• Grinding up the fuel (coal) which increases the
  surface area will speed up the reaction.
• Increasing the temperature of the fuel mixture
  will increase the rate of the reaction as well.

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Changing Gears from Reactions

• We have been talking about the heat gained or
  lost during a chemical reaction and it has been a
  load of fun.
• Now we are going to look at how heat is gained or
  lost when we look at the physical changes of
  melting, boiling and temperature change.

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Today

• If you missed yesterday copy this website.
• The answers are due on Monday.
• http//www.mrfischer.com/wp-content/uploads/23-the
  rmwebquestques.pdf
• By Monday BONUS points on Quest possible.
• Bring empty and clean 2L bottles get 1 added to
  quest grade (Max 5)
• Bring 1L bottle of vegetable oil (5)

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Heat to Change Temperature and to Change Phase

• If ice turns into water, what is needed?
• If water turns into vapor, what is needed?
• If the temperature of water increases, what is
  needed?
• HEAT!!!!

mass
q mCp?T
Change in temperature
?T Tf - Ti
heat
Specific heat
Amount of heat needed to increase the temp of 1g
of a substance by 1ºC
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Heat to Change Temperature and to Change Phase

• Specific heat (Cp) is different for every
  substance and it is different for each phase of a
  given substance.
• Cp ice 2.02 J/gºC
• Cp water 4.2 J/gºC
• Cp vapor 2.06 J/gºC
• ExHow much heat is needed to raise the
  temperature of 150g of water from 2.0ºC to 93ºC?

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Heat to Change Temperature and to Change Phase

• If ice is melted, heat is needed, but we dont
  look at the temperature.
• Energy added is used to stretch bonds not make
  the particles move faster (T).
• Types of bonds
• Intra-molecularatoms are held together inside a
  molecule.
• Inter-molecularmolecules are held together in a
  substance.

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Heat to Change Temperature and to Change Phase

• The equation we need to determine the heat
  necessary to melt a given amount of solid is

mass
q m?Hfus
heat
Heat of Fusion
Amount of heat needed to melt 1g of a solid
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Heat to Change Temperature and to Change Phase

• Heat of fusion (?Hfus) is different for every
  substance.
• ?Hfus ice 330 J/g
• ExHow much heat is needed to melt 150g of ice?

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Heat to Change Temperature and to Change Phase

• If water is boiled, heat is needed, but we dont
  look at the temperature.
• Energy added is used to break bonds not make the
  particles move faster (T).

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Heat to Change Temperature and to Change Phase

• The equation we need to determine the heat
  necessary to boil a given amount of liquid is

mass
q m?Hvap
heat
Heat of Vaporization
Amount of heat needed to boil 1g of a liquid
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Heat to Change Temperature and to Change Phase

• Heat of vaporization (?Hvap) is different for
  every substance.
• ?Hvap water 2260 J/g
• ExHow much heat is needed to boil 150g of water?

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Heat to Change Temperature and to Change Phase

• Putting it all together

Add heat boil q m?Hvap
G
Add heat and T incq mCp?T
100ºC
Add heat melt q m?Hfus
T (ºC)
L
Add heat and T incq mCp?T
0ºC
S
Add heat and T incq mCp?T
Heat (q in Joules)
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Try em!
Ask this question is the substance changing
temperature or changing phase?
If it is changing temperature, which eqn works?
If it is changing phase, which eqn works?

• How much heat is absorbed by a 6.00g piece of
  -13.0ºC ice cube when it is heated to 0.0ºC?
• 160J
• How much energy does it take to melt the 6.00g
  ice cube if it is at its melting point?
• 1980J
• How much energy is absorbed by 6.00g of liquid
  water at 0.0ºC to bring it to waters boiling
  point?
• 2500J
• How much energy does it take to turn 6.00g of
  liquid water at 100.0ºC to steam?
• 13600J
• How much energy is needed to take 6.00g of steam
  at 100.0ºC to steam at 120ºC?
• 250J

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OK...try this

• How much heat is needed to turn ice at -11ºC into
  water at 55ºC?

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Heat to Change Temperature and to Change Phase

• If a piece of hot metal is dropped in a beaker of
  cool water, what happens to the temperature of
  the metal? The water?
• So, if the water absorbs 100kJ of energy the
  metal loses
• 100kJ of energy.
• The metals temperature drops.

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Heat to Change Temperature and to Change Phase

• So, the heat lost by an object is gained by
  another object.
• Heat lost -q
• Heat gained q
• So, for the hot metal/cool water example, the
  heat gained by the water (qwater) equals the
  heat lost by the metal (qm).
• qwater -qm
• qwater qm 0

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Heat to Change Temperature and to Change Phase

• If a piece of ice melts, where does the heat come
  from?
• Something outside of the ice cube.
• If we place and ice cube in a glass of Kool-Aid
  what supplies the heat to melt the ice?
• Mostly the Kool-Aid.
• So, if the ice absorbs 100kJ of energy the
  Kool-Aid loses
• 100kJ of energy.
• The Kool-Aids temperature drops.

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Heat to Change Temperature and to Change Phase

• What if we have a 55.0g of a piece of metal, say
  iron, at 99.8ºC and we place it in a 225g of
  water at 21.0ºC.What is the specific heat of the
  metal if the final temperature of the water and
  Fe is 23ºC?

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Heat to Change Temperature and to Change Phase

• Heat lost by iron is qFe
• Heat gained by water is qH2O
• -qFe qH2O
• qFe qH2O 0
• What happens to the iron as heat is lost?
• Temperature drops.
• What equation do we use for temperature change?
• q mCp?T

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Heat to Change Temperature and to Change Phase

• What happens to the water as heat is gained?
• Temperature rises.
• What equation do we use for temperature change?
• q mCp?T
• So we can rewrite the previous eqn as
• (mCp ?T)Fe (mCp ?T)H2O 0

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Heat to Change Temperature and to Change Phase

• (mCp?T)Fe (mCp ?T)H2O 0
• (55.0g)(X)(76.8ºC) (225g)(4.2J/gºC)(2.0ºC) 0
• -4224g ºC X 1890J 0
• -4224g ºC X -1890J
• X -1890J / -4224g ºC
• 0.448 J/gºC

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Heat to Change Temperature and to Change Phase

• Another example
• What is the minimum amount of ice at 0ºC that
  must be added to the contents of a 340. mL glass
  of Kool-Aid to cool it from 20.5ºC to 0.0ºC.
  Assume Cp of Kool-Aid is the same as liquid water
  and that no heat is gained or lost to the
  surroundings.

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Heat to Change Temperature and to Change Phase

• qice qKoolAid 0
• What happens to the ice when heat is added to it?
• What happens to the Kool-Aid as heat is lost?
• The qs then are
• (m?Hfus)ice (mCp ? T)KA 0
• (m)(330J/g)(340g)(4.2J/gºC)(-20.5ºC)0
• m 88.7g ice needed

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Old Fuel

• Coal, oil and natural gas possess many of the
  properties needed in a fuel.
• So, most of the energy we use comes from these
  sources.
• These fossil fuels can be thought of as sunshine
  in the solid, liquid and gas state.
• Sunlight was captured millions of years ago in
  green plants that over the years has decomposed
  and highly compressed into the fossil fuels we
  use today.

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Old Fuel

• 2800kJ CO2 H2O ? C6H12O6 O2
• Plants require about 2800kJ of energy from the
  sun for each mole of glucose they produce.
• On the other hand we use the 2800kJ of energy per
  mole of glucose we eat.
• This energy is converted into the energy that our
  muscles and nerves use throughout the day.

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Coal

• When the Industrial Revolution began, wood was
  the major source of fuel in England.
• Over a short time all the forests were cut down
  and wood was scarceso coal took over.
• Burning 1g of coal produces 30kJ of heat while
  burning 1g of wood produces only 10-14kJ of heat.
• Coal was definitely the choice.

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Coal

• Coal has a chemical formula of C135H96O9NS.
• In addition samples of coal also contain small
  amounts of Si, Na, Ca, Al, Ni, Cu, Zn, As, Pb and
  Hg.
• The more impurities the lower the grade and the
  lower the amount of heat released during the
  burning of coal.

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Try This One

• Assuming the composition of coal can be
  approximated by the previous given chemical
  formula, calculate the mass of carbon (in tons)
  contained in 1.5 million tons of coal, which is
  the amount of coal that a typical power plant
  would burn. (Hint Mass )

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Petroleum

• Around 1950, petroleum surpassed coal as the
  major energy source in the US.
• It is liquid so it is easier to pump from the
  ground reserves, transported via pipelines and
  fed automatically to its point of use.
• Also petroleum yields about 48kJ per gram
  burnedmuch more than coal.

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Petroleum

• However, crude oil must be processed before it
  can be used.
• The crude oil is refined by a process called
  distillation into many different usable forms of
  fuels.
• It can be separated into gasoline, kerosene, gas
  oil, lubricating oil and petroleum gas.

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Manipulating Molecules

• Research has found that not all compounds
  distilled from crude oil are useful for desired
  applications.
• Chemists have devised ways to take these high
  molecular weight compounds and create smaller
  more usable compounds through a process called
  cracking.
• C16H34 is a byproduct of distillation but is not
  very useful.
• C16H34 ? C8H18 C8H16 or
• C16H34 ? C5H12 C11H22

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Seeking Substitutes

• Because the worlds coal supply is much greater
  than our available oil reserves, there is
  interest in converting coal into gaseous and
  liquid fuels that are identical with or similar
  to petroleum products.
• An old technology that does this is blowing steam
  over hot carbon called coke.
• Coke is the impure carbon that remains after
  volatile components have been distilled from
  coal.
• C(s) H2O(g) ? CO(g) H2(g)

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Seeking Substitutes

• The CO and H2 are called water gas and were used
  as energy to light cities.
• Fischer-Tropsch process for producing synthetic
  gasoline uses this reaction.
• The CO and H2 are passed over an iron or cobalt
  catalyst which promotes the formation of
  hydrocarbons.
• The hydrocarbons range in size from methane to
  5-8 carbon atoms (that are typically used in
  gasoline).

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Seeking Substitutes

• This process is economically feasible in
  locations where coal is cheap and plentiful and
  oil is scarce and expensive.
• This is the case in South Africa, where 40 of
  the gasoline is obtained from coal.
• In the future, such technology might become
  competitive in other parts of the world.

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Seeking Substitutes

• The concerns about dwindling supplies of
  petroleum have also led to the use of renewable
  energy sources.
• This generally refers to biomass which are
  materials produced by biological processes.
• Wood is one such source, but there is far too
  little wood to meet our energy demands.
• Plus we would be destroying good CO2 absorbers.

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Seeking Substitutes

• Our favorite, ethanol (C2H5OH) is another
  alternative biomass fuel getting a lot of press
  of late.
• Ethanol is formed by the fermentation of
  carbohydrates such as starches and sugars.
• Enzymes released by yeast cells catalyze the
  reaction that is typified by
• C6H12O6 ? 2 C2H5OH 2 CO2
• The burning of ethanol releases 1367kJ per mole
  burned. (30kJ/glower than 48kJ/g produced by
  gasoline)

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Seeking Substitutes

• The burning of ethanol releases 1367kJ per mole
  burned.
• Corn is being used to create ethanol and added to
  unleaded gas at 8515 to create E85 gas.
• In general, E85 gas is cheaper than unleaded gas,
  but you can only use E85 gas in certain vehicles.
• Should Oil Companies be banned  from Owning
  Ethanol Plants ?

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Seeking Substitutes

• Ethanol or flex-fuel cars are common in countries
  such as Brazil.
• They farm sugar cane and convert it to ethanol
  and run any mixture of ethanol-gas they choose.
• But by using computer sensors that adjust to
  whatever mix is in the tank, flex car engines run
  on either ethanol, gasoline, or any combination
  of the two.
• Gas-electric hybrids are another option.

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Seeking Substitutes

• Unlike hybrids sold in the US, for example, flex
  cars sold in Brazil don't cost any more than
  traditional models.
• In fact, some models are only available with flex
  engines now.
• Ethanol engines use 25 percent more ethanol per
  mile than gasoline. But ethanol usually sells at
  somewhere between a third to half of the price of
  gas.

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Seeking Substitutes

• Another potential energy source is a commodity
  that is cheap, always present in abundant supply
  and is always being renewed.
• It is garbage.

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Seeking Substitutes

• Elk River Resource Recovery Facility (ERRRF) in
  Hennepin, MN processes garbage into refuse
  derived fuel (RDF).
• ERRRF serves five area counties. Hennepin County
  contracts to deliver up to 235,000 tons of
  garbage to ERRRF each year.
• The RDF is transported to a nearby power plant,
  where it is combusted to generate electricity.
• The RDF from Hennepin County garbage produces
  enough electricity to provide power to the
  equivalent of 12,700 homes each year.

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Seeking Substitutes

• This resource recovery approach simultaneously
  addresses two major problems
• The growing need for energy
• The growing mountain of waste

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Write

• The Elk River Resource Recovery Facility has been
  the subject of a great deal of controversy for
  the county residents. The idea of generating
  usable energy from trash sounds great, until the
  facility is built in your neighborhood. This is a
  problem faced by the homeowners and residents in
  the area surrounding the plant. To address
  residents concerns, an open meeting between the
  residents and representatives of the plant is
  scheduled. Managers from the plant, engineers,
  and representatives of the state pollution
  control agency will be present. Prepare a list of
  questions that you, as a resident in this area,
  would like to see addressed at this meeting.

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The Case for Conservation

• The fundamental feature of the universe is that
  energy and matter are conserved.
• However the process of combustion degrades both
  energy and matter, converting them to less useful
  forms.
• As residents of the universe, we have no choice
  but to obey its unavoidable laws.
• The planets fossil fuel stores are limited and
  although we could go many years without running
  out, there will come an end.

86
The Case for Conservation

• The demands of the power plants in the world for
  coal, oil and gas are huge.
• Fibers, plastics, rubber, dyes, medicines, and
  pharmaceuticals are currently produced from
  petroleum.
• Once the petroleum is gone, we will need to find
  a different way to make these as well.
• On a positive note, the world is aware of this
  situation and many have been working to find
  better alternatives all the time.

87
The Case for Conservation

• To a considerable extent, taste ultimately
  influences what technology can do to conserve
  energy.
• As individuals and as a society, we must decide
  what sacrifices we are willing to make in speed,
  comfort and convenience for the sake of our
  dwindling fuel supplies and the good of the
  planet.

88
The Case for Conservation

• The costs might include higher taxes, more
  expensive gasoline, and electricity, fewer and
  slower cars, warmer buildings in the summer and
  cooler ones in the winter.
• One thing seems clear the best time to examine
  our options, our priorities, and our will is
  before we face another full blown energy crisis.

89
Review

• What does the 1st Law of Thermodynamics state?
  (a.k.a. Law of Conservation of Energy)
• Define energy.
• Define work.
• Define heat.
• What is the unit for energy?
• What is the difference between and exo and
  endothermic reaction?

90
Review

• Define activation energy and draw an energy graph
  showing an exothermic reaction.
• What is combustion?
• Draw these moleculesO2, CO2, H2O, CH4, C3H8)
• What is bond energy?
• Is bond breaking an endo or exothermic process?

91
Review

• Is bond forming an endo or exothermic process?
• What is the energy given off or absorbed for the
  reaction of octane (C8H18) with O2 to form CO2
  and H2O?
• What are three main fossil fuels used today?
• How are fossil fuels like sunshine in the solid,
  liquid or gas form.

92
Review

• How does the 1st Law of Thermodynamics
  illustrated through fossil fuels?
• How does the 1st Law of Thermodynamics
  illustrated through photosynthesis?
• What is cracking and when is it used during
  fossil fuel refinement?
• Rank the following in order from lowest to
  highest energy output per gram used petroleum,
  coal, ethanol, wood.

93
Review

• Give a reason why it is good to use wood as fuel
  and one that is not good.
• Give a reason why it is good to use coal as fuel
  and one that is not good.
• Give a reason why it is good to use petroleum as
  fuel and one that is not good.
• Give a reason why it is good to use ethanol as
  fuel and one that is not good.

94
Review

• How is coal converted to synthetic gasoline?
• What is E85?
• How is ethanol made?
• What are flex-fuel cars?
• Who is ahead of the US in the usage of ethanol
  fueled cars?
• What is being done in Hennepin MN?

95
The Other Side of the Inconvenient Truth

• Get ready to take Notes on some videos.

96
Message to Seniors

• "Senior skip day may result in the loss of
  special privileges planned for your class,
  including your senior day breakfast, the senior
  cookout on your last day, and of course
  Baccalaureate and Graduation. This class at our
  school gets out waaaaay earlier than most schools
  with the Senior Seminar, so there should be no
  need for a skip day. Please know that the
  administration will find out and will follow up
  with the appropriate consequences."
• So sayeth el Bridges