Name _______________________
Miss McGrory
APES
Period _______
Date _______________
Analysis WS 2-3
1. Discuss persistence and how it pertains to the different varieties
of pollutants.
Persistence is a measure of how long a pollutant stays in the
air, water, soil, or body. Degradable pollutants are broken down
completely or reduced to more acceptable levels by different
processes; they have a low persistence. Biodegradable pollutants
are complex chemical pollutants that living organisms break down
into more simple chemicals. Biodegradable objects too, have
relatively short persistence if they are not added at a rate greater
than they can be broken down. Slowly degradable pollutants take
decades or longer to degrade. The slowly degradable insecticide
DDT and most plastics have extremely long persistence.
Nondegradable pollutants are chemicals that natural processes
cannot break down such as lead and mercury. They have infinite
persistency.
2. What are the differences between nuclear fission and fusion
reactions?
Nuclear fissions is a nuclear change in which the nuclei of
certain isotopes with large mass numbers are split apart into lighter
nuclei when struck by neutron; each fission releases two or three
more neutrons plus energy. This in turn, creates a chain reaction
which causes more and more neutrons to become involved and
releases an enormous amount of energy. Nuclear fusion is a
nuclear change in which two isotopes of light elements, like
hydrogen, are forced together at high temperatures to form a
heavier nucleus. This can release an even more immense amount
of energy.
3. How does energy quality influence lifestyle choices?
Energy quality is a measure of energy source’s availability to
do useful work. High-quality energy is concentrated and can
perform much useful work. Examples include electricity, the
chemical energy stored in coal and gasoline, and other things. By
contrast, low quality energy is dispersed and has little availability
to do work, such as moving molecules in matter. The higher
quality the energy quality, the more likely we are to abuse our
resources and exploit the environment. This is in part what leads
to the tragedy of the commons.
4. Explain the first law of thermodynamics.
The first law of thermodynamics states that “in all physical
and chemical changes, energy is neither created nor destroyed,
although it may be converted from one form to another.”
Essentially, matter can only be destroyed by a nuclear reaction and
converted to energy, or vice versa. In a chemical or physical
reaction, this is not possible. However, it is possible to convert
from different types of energy, such as from kinetic to potential.
5. Apply the second law of thermodynamics to how gasoline is
used to power a car, electrical energy is used for incandescent light
bulbs, and solar energy is used to support living things.
When gasoline is powering a car, only a small portion of it is
actually used to drive pistons, the vast majority of gasoline escapes
with heat from the exhaust pipe. When electrical energy powers a
light bulb, most of the energy is degraded to a lower quality as
well. It is more dispersed, such as in the car, and thus only a small
portion is actually used to power the bulb. Solar energy too is
much dispersed. In a photovoltaic cell, efficiencies of ~15% are
considered extremely high, due to the dispersion of energy
throughout the system, very little of the potentially available
energy is available due to its dispersion.