Download Chapter 2 Chemistry

Chapter 2 Chemistry
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It is important to know the chemistry that
is involved in the cycling of nutrients,
resource use, and pollution.
Some of our chemicals are naturally
occurring and some anthropogenic
(manmade)
The Chemistry of Carbon, Nitrogen,
Oxygen, Phosphorus, & Sulfur
Carbon= Backbone of all organic
compounds including all of the important
molecules found in living organisms
Fossil Fuels and Carbon dioxide (important
green house gas)
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Nitrogen= Most abundant element in the earth’s
atmosphere at 78 %.
Found in the amino group of every amino acid, the
building block of protein
Nitrogen runoff from agricultural land is an important
contributor to nutrient pollution in waterways.
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Nitrous oxide is an important greenhouse gas
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Oxygen= The second most abundant element in
the atmosphere at 21 %
Most abundant element in the earth’s crust
Oxygen was added later into the atmosphere
through photosynthesis of green plants
Necessary for cellular respiration
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Phosphorus= Component of nucleic acids
and phospholipids
Sulfur is a major constituent of volcanic
eruptions and a contaminant of coal that
contributes to acid rain
Defining Matter
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Matter is anything that has mass
Found in 2 chemical forms elements &
compounds
Matter Quality= is a measure of how
useful a form of matter is to humans as a
resource based on its availability.
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High Quality Matter= easier to extract and is
concentrated. Found near earth’s surface & has
greater potential for use
Low Quality matter=located deep underground
or dispersed in ocean or atmosphere. Has little
potential for use.
Physical & Chemical Changes
Physical change is when the chemical
composition does not change. (Solid ice
melting into liquid)
 Chemical change is when rearrangement
of atoms occurs and get a different
product (Chemical reaction)
Coal + Oxygen = Carbon dioxide + energy
With chemical reactions energy is released
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Law of Conservation of Matter
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When a physical or chemical change
occurs, no atoms are created or destroyed
There is no “away” in to throw “away”
Everything remains with us in some form
We can remove harmful substances but
cannot get rid of it
Types of Pollutants
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We can always produce some pollutants
but we can always produce much less and
clean up.
Persistence is the measure of how long
the pollutant stays in the air, water, soil, or
body
4 Categories
Degradable= broken down completely
 Biodegradable= Living organisms break down
 Slowly Degradable= takes decades to degrade
Example includes insecticide DDT and most
plastics
 Nondegradable= Cannot be broken down
Examples include mercury, lead, arsenic
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Law of Conservation of Matter means we will
always face the problem of what to do with
some quantity of wastes and pollutants
Nuclear Changes: Radioactive
Decay, Fission & Fusion
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Natural Radioactive Decay: Unstable isotopes
release chunks of matter (particles)
Decay continues until it produces a stable
isotope that is not radioactive
Each isotope decays at a specific rate (This rate
is called half life)
It can be used to estimate how long a sample
must be stored before it decays to a safe level.
Experimental Design
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Most common type of experiment=
controlled experiment
Don’t forget the control!
Write a testable hypothesis (If…
then…..because)
Isolate one variable to measure and one
variable to manipulate
Experimental Design
Independent Variable is manipulated
during the experiment
 Dependent Variable is measured during
the experiment
Example: Design an experiment to
determine how soil pollution affects
elderberry bushes.
1. Select two variables, one you can
manipulate and one you can measure
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Experimental Design
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Manipulate the concentration of a
pollutant (salt)
Pick something you measure (the number
of elderberries produced by each bush)
Hypothesis: Increased salt concentration
in soil result in a decrease in the number
of berries
Experimental Design
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Don’t forget the control!
Collect and analyze data
Draw Conclusions
FRQ Practice
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Unit #1- APES- FRQ
For thousands of years, clams have been dug up
along the beaches of California for food, first by
Native Americans, and these days often by
tourists. Today, the clam population is at an alltime low, and many scientists agree that several
species of clams will inevitably become extinct in
California. Dr. Kim, a marine biologist, believes
that DDT dumped into the ocean during the
1950’s and 60’s could be another factor in the
dramatic decrease in the clam population.
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Write an argument to explain why the decline in the
clam population could be considered an example of a
tragedy of the commons.
Identify and describe two strategies that could be
employed to prevent any decline in the clam population
due to a tragedy of the commons.
Design a controlled experiment to support or refute
the claim by Dr. Kim that DDT is playing a role in the
clam’s demise. Include a detailed description of the
experiment that includes the hypothesis being tested, a
description of the data being collected, and identification
of the dependent and independent variables in the
experiment.