I. Matter

I. Matter

Three usual forms of chemical Matter:

• Elements
  106, or 108 or 109 unique substances composed of subatomic particles (92 naturally occurring)
  Example:
  Na, Mg, Cu, C, Si, P, Cl, He, U Metals, Nonmetals, Gasses

• Compounds
  Pure substance that can be broken down into elements > 10 million identified
  Example:
  CO2, NaCl, C12H22O11 (Sucrose)

  Mixture
  Mixtures exist together without chemically combining
  Example:
  Air 78% N2 and 21% O2
  (other examples, soil, rocks, living - plants, animals)
  

Conceptual models of organizations of matter in nature.

Subatomic Particles

Ions

• Elemental Ions
  H+, Na+, Cl-, Zn(+2)

• Polyatomic Ions
  NH4+, NO3-, PO4(-3), SO4(-2), CN-, OH-, H3O+

Isotopes

Z = # of protons (atomic number)
A = # of protons and neutrons (mass number)
N = # of neutrons

N = A - Z

Example

Compounds

General classification:

Organic - carbon containing compounds

Inorganic - all others except carbides and pure carbons (graphite, diamonds etc.)

Compounds are classified in groups of similar properties:

plastics
sugars
proteins
fats
oils
alcohols
acids

Molecules of specific interest to environmental science:

• Hydrocarbons
  CH4 methane

• Chlorinated Hydrocarbons
  C14H9Cl5 DDT
  C12H5Cl5 a PCB

• Chlorofluorocarbons (CFCs) CCl2F2 Freon - 12

II. Energy

"Energy, not money is the real currency of the world"

- Miller

Why does he say this?

It is a key commodity in modern day industrial societies.

An essential and fundamental resource.

Energy - the capacity to do work

Kinetic Energy
- energy because of motion and mass
Example: Heat - in motion of molecules

Potential energy
- stored energy "potentially available"
Example: Sugar - in chemical bonds

The Earth is not a closed system

The Sun is Earth's energy source

The most significant energy source
~ 1.0 kW € m^(-2) per day (US on a clear day)

The sun is responsible for essentially all energy used on the earth.

This energy drives all the cycles and energy sources we will study
carbon, oxygen, water, nitrogen, wind, oil, coal, biomass, solar, etc.

Commercial Energy

Commercial energy use by source in 1991 for the world, the United States, MDCs, and LDCs.

US population - 4.7% of world population, but 25% of world commercial energy consumption

Current statistics

If LDCs rise to a level equal to US energy consumption rates by 2025, the total commercial energy output must go up by 5 times.

What would this do to CO2 output?

Comparison and contrast

Some notes on energy:

It is not just energy, but the forms of energy

Portable energy sources have freed civilization to be mobile.

What type of energy is used for labor saving devices outside the home?

Questions

Is technology dependent on energy?

What would you have to live without today if gas was not available (gasoline, natural gas, propane etc.)?

What would you have to live without today if batteries were not available?

Can you exist as you are accustomed without portable energy sources?

Has portable energy made a significant difference in human lifestyle?

III. Electromagnetic Radiation as Energy

Electromagnetic radiation has a dual nature that has perplexed scientists for over a century.
It is a combination of waves and it has energy.

It can be thought of as discrete packets of energy or photons.

Electromagnetic radiation also has a wave character.

Propagating Energy and Magnetic Fields

Important parameters involved with an electromagnetic wave

The distance between the maximum of either the electrical or magnetic component.

The number of oscillations of the field that occurs per second.

Note: The frequency is determined by the source and remains invariant regardless of the media traversed by the radiation.

It is also equal to 1/p where p is the period of the radiation and where p the period is the time required for one cycle of maximum to pass a given point.

Velocity of Electromagnetic Radiation

In vacuum

Wavelength and frequency are related to the energy of a photon, E, by Planck's constant, h, 6.62x10^(-34)J sec, and c, the velocity of light (3.00 x 10^(8) m/sec) in a vacuum.

Relative Energy

The electromagnetic spectrum.

Why is ultraviolet energy ionizing radiation?

Energy per photon is

So What?

Why are microwaves not an ionizing form of ionizing radiation?

Spectroscopes use grating to separate the spectrum

Example of Na line energy vs x-ray line energy

Changing to electron volts as units:

For an x-ray of 5.3 Å the energy is:

So 5.3 Å x-ray is approximately 1000 times as energetic as the visible line of 589 nm Na atom.

Why would Na lights take less energy than Hg lights?

What consumes energy in gaseous vapor lighting?

"Incandescent" - Emitting visible light as a result of being heated.

For Mercury (Hg), the most intense line is at 2535.5 Å the energy is:

Note: Ionization energy of Hg > ionization energy of Na

Demonstration of line spectra (grating spectrophotometers)

IV. Changes in Matter

Physical Changes in Matter

Example:

Requiring addition or subtraction of heat.

Chemical Changes in Matter

Example:

Most reactions are not complete. An equilibrium exists where both the reactants and products coexist, but with indifferent ratios.

Generic Reaction

Equilibrium Constant - Keq

Conservation of Matter (non nuclear)

The earth is essentially a closed system as far as matter is concerned.

"In all physical and chemical changes, we can't create or destroy any of the atoms involved. All we can do is rearrange them into different spatial patterns (physical change) or different combinations (chemical change)."

Conservation of Energy (non nuclear)

This statement is the:

First Law of Thermodynamics

(Energy is transferred as work or heat)

Work = force x displacement
Heat = spontaneous flow from high temperature areas to low temperature surroundings

The author refers to "energy quality" - a relative scale of energy usefulness

Second Law of Thermodynamics

Entropy (S) is a direct measure of the randomness or disorder of a system.

Example: Rank the entropy of a phase change

Ssolid > Sliquid > Sgas

"Although in any process energy is neither created nor destroyed, (first law) the use of energy inevitably leads to a lowering of the "quality" of the energy. ... the energy has a decreased capacity to perform further work. The energy, although conserved, is also to be degraded."

Heat loss to the environment is an increase in entropy and a decrease in energy.

High quality energy (usable energy), transformed into low quality energy or entropy, is unusable.

Examples: To keep the order of molecules and structure of your body, you must use energy or it degrades and increases in entropy.

A five year old's bedroom requires large amounts of energy to prevent entropy (tendency toward randomness) from taking over.

"All forms of life are tiny pockets of order (low entropy) maintained by creating a sea of disorder (high entropy) in their environment. The primary characteristic of any advanced industrial society is an ever-increasing flow of high-quality energy and matter resources to maintain the order in human bodies and the larger pockets of order we call civilization."

We cannot eliminate entropy but we can reduce it.

How?

Efficiency reduces waste heat and minimizes entropy.

Categories of the quality of different sources of energy.

The lower the quality of energy, the less work that can be done with it.

Nuclear Change

(physical, chemical, nuclear)

Three types of nuclear events:

• Natural radioactive decay
• Nuclear fission
• Nuclear fusion

Some nuclear matter is converted into energy and this is what we use as we react nuclear fuel.

"In a nuclear change, the total amount of matter and energy involved remains the same."

Natural Radioactivity

Three (common) particles or energies emitted in nuclear reactions

Helium nucleus (2 protons, 2 neutrons)

conversion of neutron to proton in nucleus

electromagnetic radiation
very short wave length, high energy

Penetration power of the three principal types of ioning radiation emitted by radioactive isotopes.

Other particles or energies emitted in nuclear reactions

Positron
positive electron from nucleus with p to n result -1 atomic # same atomic weight

Electron Capture
inner orbital electron captured by nucleus p to n, same atomic weight, -1 atomic #.

Neutron decay
nucleus ejects a neutron atomic weight -1, atomic # same.

How do you get an electron from the nucleus when there are no electrons in the nucleus (Beta particle)?

Positron is analogous to a positive electron.

per photon

Nuclear Fission and Fusion

Fission:

Fission of uranium-235.

A chain reaction of large mass isotopes such as U-235 requires:

• High purity of U-235
• Critical mass

Example of Uranium fission:

How much energy?

2 x 10^(13) J/mol
(20,000,000,000,000 J/mol; 20 trillion J/mol)

A nuclear chain reaction.

Fusion:

Fusion reaction.

"Sun power"

Scientific copy is:

(Unfortunately, we need a couple million degrees)

Radon

Home 2.7 x 103 pCi/L (equated to 455,000 chest x-rays/yr.)
EPA action level 4 pCi/L
Out door level 0.2 pCi/L

Why?

Uranium ore - to - Radium - 226 to Radon - 219, 220, 222 U - 238

Radon - 219, 220 1/2 life ~ seconds

Radon - 222, 3.8 days 1/2 life

Radon - 222 to Polonium - 218 and Polonium - 214 alpha-emitters 1/2 life 3.1 min. and 2 x 10-4 s respectively

Problem:

Radon - inert
Po - reactive and clings to lung tissue

alpha-penetration ~ 70 µ m ~ 2x the cell membrane thickness of lung tissue thus access to DNA is the proposed cause of lung cancer.

Specific location in lung

5,000 to 20,000 deaths per year attributed to Radon.

Detection - Yes
Epidemiology - Yes (dose response)
Engineerable barriers - Yes

V. Energy Consumption

41% is wasted due to the second law of thermodynamics and inefficient transfer mechanisms. (resistance losses, etc.)

43% is wasted unscientifically and could be recovered.

Matching energy use to quality of energy

Energy efficiency of some common energy conversion devices.

Comparison of net energy efficiency for two types of space heating.

Net energy efficiencies for various ways to heat an enclosed space.

Net useful energy ratios for various energy systems over their estimated lifetimes.

"We cannot recycle waste heat, we can only conserve energy"

Discussion of energy use in the US

Flow of commercial energy through the U.S. economy.

A throwaway society's energy and matter flow system.

A sustainable-Earth society's energy and matter flow system.

Waste heat

Why is solar heating (passive) so efficient?
Where does the energy come from?

In what form of energy, does the Sun deliver energy to Earth?

Why is a fluorescent light 22% efficient and an incandescent 5%?
What energy form is given off?
What energy form is wasted?
Why?

Science is simply common sense at its best - that is, rigidly accurate in observation, and merciless to fallacy in logic.

- Thomas Huxley

"Science is built up with facts, as a house is with stones. But a collection of facts is no more a science than a heap of stones is a house".

- Jules Henri Poincare'

EXAMPLE: (Lord Kelvin)

Aluminum can recycling and its relationship to (US) population.

Examples of differences in matter quality.

energy

100 watts for 100 hr. or 100 W € h, or 0.1 kW € h

Average US home requires 30 kW € h per day.
Sunlight in a day ‰ 1.0 kW € m^(-2)
10 cents per US kW € h

Electricity to produce 1 Aluminum can from ore is 0.1 kW € h.

Electricity saved by recycling 95%
Air Pollution saved by recycling 95%
Water Pollution saved by recycling 97%

30 kW € h per day per home / 0.1 kW € h per can = 300 cans per home per day to run 1 US home (1.1 x 10^(5) per yr. or 110,000)

The energy savings from recycling the Al cans in the US 83,000,000,000 (8.3 x 10^(10)) Al cans produced in 1990

Would supply the energy to 2.8 x 10^(8) or 280,000,000 homes for a day

or 7.7 x 10^(5) or 770,000 homes for a year.

Other conversion factors:
Power - is the rate that energy is used, the SI unit of power is the watt.
1 W = 1 J € s^(-1) ; 1 joule (J) = 1 kg € m^(2) € s^(-2)
100 W = 100 J € s^(-1)
kilowatt-hour kW € h, is 1 kW operating for 1 hr.

EXAMPLE (continued): Aluminum Can Example (World) Population

Let us look at this projected on the world Population in the year 1992

Assume
US population 250,000,000 (in 1992) (2.5 x 10^(8))
(332 cans per person per year in the US)

World population (in 1992) 5,500,000,000 (5.5 x10^(9))
{actually 6 billion but 0.5 don't like Coke}
Assume
same number of cans per person in the entire world
total number of cans = 1.8 x 10^(12) cans per year (1,800,000,000,000 )
2 trillion can per year

Energy
1.7 x 10^(7) homes worth of electricity per year at US energy rates
or 17,000,000 or 17 million homes per year (7% of US homes)

Energy in the year 2006 with 7 billion people with 10 billion
2.1 x10^(7) (electricity for 21,000,000 or 21 million homes per year)

20?0
3.0 x 10^(7) (electricity for 30,000,000 or 30 million homes per year)

Yes, but we are recycling them.

only ~ 60% are recycled so we still have the electricity for 0.3 million homes being discarded in the US in 1992, and the potential for 3 million in 2006 if others follow our example.

Other considerations of population exponential growth

Suppose it is not Al cans, but the consumption of energy

Notes Table of Contents

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Created and maintained by
Jim Ferguson
Revised 9/13/95.