Environmental Systems
Chapter 2
Matter
“anything that occupies space and has mass”
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Atoms
Molecules
Periodic Table
Atomic Number
http://science.howstuffworks.com/laser1.htm
• No atoms are ever destroyed or created, but the
bonds may change between them
a. law of conservation of matter
- “ matter cannot be created or destroyed; it
can only change form”
Radioactivity
• Unstable isotopes are radioactive
• Radioactive decay
a. spontaneous release of material from nucleus
ex) Uranium-235 (235U)
• Half-life
a. measurement of radioactive decay
Chemical Bonds
• Covalent Bonds (sharing of e-)
a. CH4 (methane)
• Ionic Bonds (transfer of e-)
a. NaCl (salt)
• Hydrogen Bonds (unequal sharing of e-)
a. weak
b. H2O
Properties of Water
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Surface tension
Capillary action
Boiling and freezing point
Acts as a solvent
http://environment.nationalgeographic.com/environment/photos/freshwater-insects/
pH
• Acid
a. dissociates into positively charged H+ and
negatively charged ions
b. HNO3 and H2SO4
• Base
a. dissociates into negatively charged OH- ions
and positively charged ions
b. NaOH
http://sanibelseaschool.org/classroom/ph
Organic Molecules
• Organic v. Inorganic Compounds
• Examples of Organic Compounds
a. Carbohydrates
b. Lipids
c. Proteins
d. Nucleic Acids
Energy
• “ability to do work, or transfer heat”
• Majority on Earth derives from the Sun
Forms of Energy
• Joule: basic unit of energy (J)
• Energy and Power
a. energy-ability to do work
power-rate at which work is done
therefore, energy = power X time
power = energy / time
• Kinetic and Potential Energy
a. Potential-stored energy not yet released
ex) water behind a dam
b. Kinetic-energy of motion
ex) electricity created from water captured
by dam
Energy Laws
• 1st Law of Thermodynamics
a. “energy is neither created nor destroyed”
• 2nd Law of Thermodynamics
a. “when energy is transformed, the quantity
of energy remains the same but its ability
to do work diminishes”
Systems
• Open System
a. exchange of matter or energy across system
boundaries
ex) ocean
• Closed System
a. matter and energy exchange across the
boundaries does not happen
ex) underground cave system
• Input
a. additions to a system
• Output
a. losses from the system
Steady State
• “inputs equal outputs so that the system is
not changing over time”
• Allows us to know if the amount of a resource
or pollutant is increasing, decreasing or
staying the same
Feedbacks
• Positive Feedback Loop
a. amplifies change
b. births in regards to human population
• Negative Feedback Loop
a. responds to a change by returning to its
original state to reach homeostasis
b. thermostat