Notes

Transcript Notes

I. ENERGY • Common: Heat, light, and electricity • Other forms: mechanical energy, chemical energy, and nuclear energy.

• These forms of energy meet the energy needs of the people on Earth.

ENERGY 

Energy cannot be created or destroyed

 Energy can, however, be changed  The storage, transfer, and conversion of energy is the driving forces behind all life on Earth

A. THE NEED FOR ENERGY 1.

A fuel is any substance from which energy can be obtained Electricity is generated by the conversion of other forms of energy This conversion is not 100 percent efficient. • Some energy is converted to heat, light, or sound

THE NEED FOR ENERGY

 4.

Non-renewable resource

– a resource that is used faster than it is replaced in nature  Ex. Fossil Fuels, Sand, Metals  5.

Renewable Resource

– a resource that is replaced in nature faster than it is used.  Ex. Oxygen, Carbon Dioxide, Water

B. Changing Energy Needs 1.

Hunter-gatherer societies ○ Light, heat, and cooking ○ Wood met needs

Changing Energy Needs

 2. Agricultural societies  Domesticated animals ○ energy sources for plows and other farm equipment

Changing Energy Needs

• 3. Industrial Revolution • Machines take over tasks ○ Farm equipment: horse-drawn plow gave way to tractors and harvesters  Fuel consumption increases due to manufacturing and use of machines

C. Organic Fuels

Organic Fuels:

Contain carbon b.

Were once part of living organisms Also contain hydrogen • 2. A compound composed only of carbon & hydrogen is called a

hydrocarbon

Organic Fuels

Hydrocarbons may contain impurities  other chemicals, such as sulfur or lead compounds  Impurities contribute to the pollution

4. Fossil Fuels

 Stored energy from ancient organisms can be used today as fuel source  Ex. Oil, Coal, Natural Gas

D. Coal

plants + swamps + sediment + time = Coal  Formed when ancient plant material is compressed below sediment  Rock that is an organic fossil fuel

Coal

 Heat & pressure:  Forces out water  Increases the carbon concentration 

Increased

carbon concentration means

Increased

energy and

less

released during combustion.

smoke

1. Stages in Coal formation

Peat 2.

Lignite 3.

Bituminous Coal 4.

Anthracite

a. Peat

 Found on Earth’s surface  Compressed plant material  High water concentration  Low energy production  Burns smoky  Brittle and brown  Low carbon concentration  Resembles decaying wood

Lignite

• Compressed peat • Lower water concentration • Soft brown coal (40% carbon) • Releases little smoke and burns quick • Found below surface - Mined

c. Sub-bituminous coal

 Type of coal whose properties range from those of lignite to those of bituminous coal  Used primarily as fuel for steam-electric power generation

d. Bituminous coal

 Soft black coal  Most abundant in USA •  Forms deep below surface – Mined Less water & fewer impurities than lignite • Higher carbon concentration (85%) • Releases little smoke and burns hotter than lignite • Widely used in industries - power plants

d. Anthracite coal

 Metamorphic rock  Shiny black color  Least water, fewest impurities  Highest carbon concentration (95%)  Located deeper in the ground than any of the other forms of coal  Burns the hottest with the least amount of smoke  Most expensive

E. PETROLEUM AND NATURAL GAS  Fossil fuels can occur in the three phases of matter.  Coal - solid  Petroleum - liquid  Natural Gas - gas

1. Petroleum

organic material + shallow seas + sediment + time = Petroleum • • Syrupy black liquid fossil fuel Formed from ancient plankton and other microscopic protists, plants, and animals

•

Impermeable

- water & other liquids cannot pass through it.

•

Permeable

– water & other liquids can pass through it.

Impermeable Shale Permeable Sandstone Impermeable Shale

Oil Wells

• Pressure builds up • Gusher: drilled well into a pressurized pool of oil - shoot upward • Where there is little or no pressure, oil must be pumped to the surface

a. Petroleum

• One of the world's most important resources • Separated or refined to make a variety of products • Gasoline • • • Jet fuels Motor oil Heating oil • Kerosene

Petroleum examples cont’

 Grease and lubricants used to reduce friction are petroleum by products  The asphalt, synthetic fabrics, and plastics are also made from petroleum

Petroleum

b. Worldwide population increases so does the demand for petroleum

2. Natural Gas

Mixture: 

Methane - major hydrocarbon

 Ethane - minor hydrocarbon  Propane -minor hydrocarbon  Trace amounts of: ○ Hydrogen sulfide ○ Carbon dioxide ○ Nitrogen ○ Helium

Natural Gas

b. Use:  Industry  Homes and businesses for heating – burns cleaner  Household appliances  Does not have to be converted to electricity first; more efficient

Natural Gas

 Household appliances Ex.  Stoves  Water heaters  Clothes dryers

Natural Gas

c. Natural gas forms in much the same way as petroleum  Often found trapped above petroleum pools  Sometimes viewed as waste of drilling oil

Homework Review - Homework Compounds that contain only carbon and hydrogen are (a) fuels; (b) fossil fuels; (c) organic fuels; (d) hydrocarbons.

Homework Review - Homework Energy conversion is not 100% efficient because energy is lost in the form of (a) light (b) heat (c) sound (d) all of the above

Homework Review - Homework The type of society that has the greatest energy needs is the (a) hunting society; (b) gathering society; (c) industrial society; (d) agricultural society.

Homework Review - Homework The first stage in the formation of coal is (a) lignite; (b) peat; (c) anthracite; (d) bituminous coal.

Homework Review - Homework The type of coal that has the highest carbon content is (a) peat; (b) lignite; (c) bituminous coal; (d) anthracite.

Homework Review - Homework The most abundant form of coal in the United States is (a) peat; (b) lignite; (c) anthracite; (d) bituminous coal.

Homework Review - Homework Coal is to fossil fuel as (a) Petroleum is to crude oil (b) Peat is to coal (c) Methane is to swamp gas (d) Alcohol is to biomass fuel

Homework Review - Homework Crude oil is another name for (a) alcohol; (b) methane; (c) peat; (d) petroleum.

Homework Review - Homework Petroleum: plastics as (a) alcohol: gasoline; (b) coal: carbon; (c) garbage: electricity; (d) industry: fuels.

Homework Review - Homework Mines: coal as (a) petroleum: refineries; (b) corn: alcohol; (c) land: agriculture; (d) wells: petroleum

Homework Review - Homework The use of corn to make alcohol is an example of (a) bioconversion; (b) fossil fuels; (c) hydrocarbon; (d) refining.

Homework Review - Homework Of the following the only example of a biomass fuel is (a) coal; (b) petroleum; (c) wood; (d) natural gas.

Homework Review - Homework The process by which alcohol is made by yeast is called (a) fermentation; (b) bioconversion; (c) purification; (d) distillation.

Homework Review - Homework Unlike fossil fuels, biomass fuels (a) do not release carbon dioxide; (b) are renewable resources; (c) are buried beneath the surface; (d) are not products of living things.

OTHER ORGANIC FUELS



OBJECTIVES:

 Describe some of the problems associated with the use of fossil fuels  Compare biomass fuels to fossil fuels, and give an example of a bioconversion technique

F. Problems associated with the use of fossil fuels

availability & pollution ○ The availability problem  fossil fuels are not renewable  All available - have already formed

Problems with Fossil Fuels cont’ • Coastal states and offshore drilling • risk of environmental damage • oil spills • widespread habitat alteration

Problems with Fossil Fuels

 An alternative - depend on the oil that are already known to exist  Location, Location, Location…  Operation Desert Storm - supply and demand

Problems with Fossil Fuels

Pollution • various kinds, especially air pollution a.

release carbon dioxide 4.

Increased use of fossil fuels since the Industrial Revolution – increased carbon dioxide in the atmosphere by more than 20% – Greenhouse Effect

Problems with Fossil Fuels

Obtaining fossil fuels is Dangerous 6.

Natural gas – combustible 7.

Coal miners  Suffocation by natural gas  Explosions of natural gas and coal dust

Coal Mine Explosion

G. Biomass Fuels

A fuel formed from the products of living organisms. Ex. wood, garbage, methane, and alcohol Renewable Resource – Can be produced

4. Wood

Cheap, used mostly in developing nations • Cost and availability Large amounts of time spent searching b.

Smoke and high carbon dioxide c.

Can be damaging to natural forests

5. Garbage

Much is largely organic materials b.

About two-thirds can be burned c.

Heat water d.

Produce steam • • Turn turbines Bingo… electric

6. Methane

• • • Swamp gas: produced in swamps from decaying plants naturally produced form of methane b.

Decaying garbage in dumps also produces methane c.

Methane removed from swamps and garbage dumps is used as a fuel

7. Alcohol

Bioconversion

: the conversion of organic materials into fuels • Ex. Sugar cane or corn to make alcohol b.

• Ethanol Yeast – Fermentation i.

Liquid biomass fuel Burns cleanly & Renewable

Alcohol

• Brazil - 2 million cars fueled by ethanol ii.

Gasohol is a mixture of 90 percent gasoline to I0 percent ethanol • Future: Engines that run on alcohol made from sunflower or peanut

Objective Revisited

 Describe some of the problems associated with the use of fossil fuels and what you think should be done to overcome these problems

Objective Revisited

 Compare biomass fuels to fossil fuels, and give an example of a bioconversion technique

Covalent and Ionic Bonding

II. ATOMS AND RADIOACTIVITY

Atoms – Basic building blocks of matter  Composed of:

Protons

Neutrons Nucleus 3.

Electrons

 Neutral Atom # of p+ = # of e -

The Atom

Subatomic Particle Location Charge Mass (amu = atomic mass unit) Proton (p + )

Nucleus + 1 amu

Neutron (n 0 )

Nucleus Neutral 1 amu

Electron (e )

Outside Nucleus ~0 amu

Helium 1 Å = 1 ten billionth of a meter

B. Atoms and Isotopes

AII atoms of the same element have the same number of protons in their nuclei.

Atomic Number

- # of p+ Ex. O = 8 protons /atomic number is 8

Atomic Mass/ Mass #

= # of protons & neutrons in the nucleus of an atom

Atoms and Isotopes

Individuals atoms of the same element may have different mass #’s because the # of

neutrons

in the nucleus can vary.

Isotope

: same element but different mass number – different number of neutron.

Isotopes

Ions vs. Isotopes

Change in Number of Electrons Change in the Number of Neutrons

No change in mass Change in charge Formation of an

ion

Change in mass No change in charge Formation of an

isotope

C. Radioactivity



Radioactivity

– unstable isotopes of atoms, emitting particles & energy from their nuclei as they decay  Studied by Marie Curie

 Ex. H-1 is not radioactive, nor is H-2. H-3 is radioactive.

2. Three Types of Radiation

Alpha particles are made up of two protons and two neutrons b.

A beta particle is a

high-speed electron

Gamma rays are a form of electromagnetic radiation

Radioactivity

 Alpha decay process changes one element into another

3) Half-life

: the amount of time it takes for half of the atoms in a sample of a radioactive element to decay

Objective Revisited

 Describe the structure of the atom and the atomic nucleus. Draw an image of a planetary model of an atom and a electron cloud model. Make sure to label the three subatomic particles and give the charge and mass for each.

D. REACTIONS AND REACTORS 1.

Energy holds protons and neutrons together

Nuclear Fission-

splitting the atom; releases energy Can be used to Generate electricity

Nuclear Fission

Uranium-235 most used i.

ii.

Splits when struck by a neutron When U-235 splits, it releases energy & forms new nuclei, called Daughter nuclei • • Often barium or krypton Often radioactive

E. Nuclear Reactors

Nuclear reactors function very similarly to fossil fuel power plants.

Energy is released by nuclear reaction  Energy is heat  Heat boils water  Steam Rises  Steam Turns Turbines  Generates Electricty

Look Familiar?

How About Now?

Nuclear Reactors

3. Water: a.

Acts as a coolant preventing the core from melting b.

Slows the movement of the neutrons released during the chain reaction

Nuclear Reactors

c. control rods  regulate the speed of the chain reaction i. made of cadmium, boron, or other materials ○ absorb neutrons ○ regulate heat production  coolant water may reach temperatures above 275 °C

Nuclear Fission vs. Nuclear Fusion

RADIOACTIVE WASTE

•

OBJECTIVES

– Define radioactive waste, and explain the dangers that arise from it. – State the problems involved in the safe disposal of radioactive wastes.

F. RADIOACTIVE WASTE

1. Produced by Nuclear power plants  ~32 metric tons typical nuclear/year ○ Reprossessed into 1.5 tons of extremely radioactive – Dangerous  Large amounts of low-level waste

RADIOACTIVE WASTE

• Radiation is unhealthy for living things • Actively dividing cells • blood-cell producing bone marrow • skin cells

RADIOACTIVE WASTE

 Radiation Exposure  Large doses ○ including skin burns ○ anemia ○ death  Changes in DNA ○ long-term effects ○ cancer ○ genetic mutations

RADIOACTIVE WASTE

4. Radiation exposure  measured in rems  Average ○ 0.2-0.5 rems / year

RADIOACTIVE WASTE

 Background radiation mostly comes from naturally occurring elements in our surroundings  Radiation exposure varies widely, depending on where a person lives and where he or she works

G. Types of Waste

1. High-level waste  Radioactive wastes that emit large amounts of radiation  used uranium fuel rods  control rods  water used to cool and control the chain reactions a.

Very Dangerous – May Also Be Poisonous b.

May be radioactive for tens of thousands of yrs

Types of Waste

2. Medium-level and low-level wastes:  Not as radioactive as high-level wastes  larger volume of these wastes is generated • Ex.

• mine wastes scattered around a uranium mine • contaminated protective clothes of a power plant worker

Types of Waste

• Low-level radioactive wastes • Also produced by hospitals & laboratories • Less obvious damage to health than high level wastes • More common than high level wastes • May pose a greater health risk to human health

H. Waste Disposal

• The contaminants may have long half-lives, taking thousands of years to decay • Low-level wastes can be dangerous for 300 years or more

H. Waste Disposal

1. High-level wastes may be dangerous for tens of thousands of years • • • • Plutonium-239 half-life of 24,000 years dangerous for 192, 000 years deadly poison, even in small amounts

Waste Disposal

2. Long half-lives = serious disposal problem 3. Must be sealed in containers that will not corrode for thousands of years 4. U.S. government seal the wastes in glass a.

must be geologically stable Earthquake or Volcanoes could cause spill Must be stored deep under the ground (costly)

Waste Disposal

• Almost all the high-level radioactive wastes in the world have not been disposed of permanently • They sit in storage tanks outside nuclear power and weapons plants

Waste Disposal

• In many cases, these tanks have begun to leak, contaminating the groundwater and releasing radioactive wastes into the environment

Waste Disposal

 These wastes must be permanently removed before the contamination gets worse  The government predicts that the cleanup of 20 of the most contaminated nuclear weapons sites in the United States could cost $600 billion

Waste Disposal

 Low-level wastes  pose disposal problems  often buried  enclosed in concrete and dropped into the ocean  Exposes environment to contamination  Medium-level wastes • • have not been disposed of permanently presents many of the same problems as high-level wastes

I. Safety and Cost

• If the cooling and control systems in a reactor core fail, the chain reaction can no longer be controlled • The core will grow hotter, causing the fuel rods and even the reactor vessel to melt •

Meltdown

Safety and Cost

 Full meltdown • release huge amounts of radiation • plants are built to avoid meltdowns or contain them if they occur • In April I986, however, one core of the Chernobyl nuclear power plant in Ukraine did melt down

 The Chernobyl plant was old and lacked many of the safety features built into newer plants  The accident itself was caused by human error

 The severity of this accident and the problems with radioactive waste disposal has led many people to question the wisdom of using nuclear power  Nuclear power plants are also very expensive because the required safety measures are very costly

Homework Review

Protons and neutrons are found together in the part of the atom called the (a) alpha particle; (b) electron; (c) nucleus; (d) isotope.

Homework Review

Protons and neutrons are found together in the part of the atom called the (a) (b) (c) nucleus; (d)

Homework Review

Two atoms of the same element with different mass numbers are called (a) isotopes; (b) nuclei; (c) electrons; (d) neutrons.

Homework Review

Two atoms of the same element with different mass numbers are called (a) isotopes; (b) (c) (d)

Homework Review

One kind of radiation not released by radioactive decay is (a) alpha particles; (b) free protons; (c) beta particles; (d) gamma rays.

Homework Review

One kind of radiation not released by radioactive decay is (a) (b) free protons; (c) (d)

Homework Review

All isotopes of an element contain the same number of neutrons.

TRUE or FALSE

Homework Review

All isotopes of an element contain the same number of neutrons.

FALSE, Protons

Homework Review

Beta particles contain two protons and two neutrons

. TRUE or FALSE

Homework Review

Beta particles contain two protons and two neutrons

. FALSE, Alpha

Homework Review

The fuel most commonly used in fission reactions is (a) Np-239; (b) U-238; (c) U-235; (d) Pu-239.

Homework Review

The fuel most commonly used in fission reactions is (a) (b) (c) U-235; (d)

Homework Review

Devices that absorb neutrons and are used to control the speed of a fission reactor are called (a) reactor vessels; (b) fuel rods; (c) containment buildings; (d) control rods.

Homework Review

Devices that absorb neutrons and are used to control the speed of a fission reactor are called (a) (b) (c) (d) control rods.

Homework Review

A fission chain reaction begins when an atom of U-235 is struck by a neutron.

TRUE or FALSE

Homework Review

A fission chain reaction begins when an atom of U-235 is struck by a neutron.

TRUE

Homework Review

In a fission reaction, some of the mass of the original atom is converted to energy.

TRUE or FALSE

Homework Review

In a fission reaction, some of the mass of the original atom is converted to energy.

TRUE

Homework Review

Each year, an average person in the United States is exposed to a radiation level of (a) 2 rems; (b) 0.2 rems; (c) 20 rems; (d) 200 rems.

Homework Review

Each year, an average person in the United States is exposed to a radiation level of (a) (b) 0.2 rems; (c) (d)

Homework Review

Pu-239 has a half-life of (a) 24 years; (b) 240 years; (c) 2400 years; (d) 24 000 years.

Homework Review

Pu-239 has a half-life of (a) (b) (c) (d) 24 000 years.

Homework Review

Losing control of the fission reaction in a reactor core may result in a (a) cooldown; (b) meltdown; (c) draindown; (d) cooling tower.

Homework Review

Losing control of the fission reaction in a reactor core may result in a (a) (b) meltdown; (c) (d)

Homework Review

The number of people forced to evacuate because of the Chernobyl accident was (a) 1,160; (b) 11,600; (c) 116,000; (d) 1,160,000.

Homework Review

The number of people forced to evacuate because of the Chernobyl accident was (a) (b) (c) 116,000; (d)

Homework Review

Radon gas is responsible for 25 percent of the radiation in most U.S. homes.

TRUE or FALSE

Homework Review

Radon gas is responsible for 25 percent of the radiation in most U.S. homes.

FALSE, 55 percent

Homework Review

Plutonium must be stored for 192,000 years before it is safe.

TRUE or FALSE

Homework Review

Plutonium must be stored for 192,000 years before it is safe.

TRUE

Homework Review

The cleanup of the 20 most polluted nuclear weapons facilities in the United States will cost $600 billion.

TRUE or FALSE

Homework Review

The cleanup of the 20 most polluted nuclear weapons facilities in the United States will cost $600 billion.

TRUE

Objective Revisited

 Visually explain how changes in human societies have changed the demand for energy

Objective Revisited

 In a complete sentence describe the structure of organic fuels

Objective Revisited

 List the stages of coal formation and describe the characteristics of each stage.

Objective Revisited

 Using the map of the United States provided for you in you packet describe to areas where coal deposits are found. Generalize the type of coal found and the location.

 Utilize the next slide to help clarify colors

PETROLEUM AND NATURAL GAS •

OBJECTIVES:

• Describe the processes of petroleum formation and extraction. • List several uses for petroleum and natural gas.

Objective Revisited

• In your own words or using pictures describe the processes of petroleum formation and extraction.

Objective Revisited

 Think back on the uses for petroleum and natural gas mentioned in this chapter so far. List which uses you personally experience in an average month.

ATOMS AND RADIOACTIVITY

• OBJECTIVES: – Describe the structure of the atom and the atomic nucleus. – Explain how unstable nuclei become stable by releasing radiation.

REACTIONS AND REACTORS

• OBJECTIVES – Discuss the fission chain reactions that power nuclear reactors – Diagram the structure and function of a nuclear reactor.

Objective Revisited

Diagram the structure and function of a nuclear reactor.

OBJECTIVE REVISITED

Define radioactive waste, explain the dangers that arise from it and state the problems involved in the safe disposal of radioactive wastes.

OBJECTIVE REVISITED

Write a personal response to your thoughts about the Chernobyl accident.