Environmental Systems Chapter 2
Matter “anything that occupies space and has mass” Atoms Molecules Periodic Table Atomic Number
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 ( 235 U) Half-life a. measurement of radioactive decay
Chemical Bonds Covalent Bonds (sharing of e-) a. CH 4 (methane) Ionic Bonds (transfer of e-) a. NaCl (salt) Hydrogen Bonds (unequal sharing of e-) a. weak b. H 2 O
Properties of Water Surface tension Capillary action Boiling and freezing point Acts as a solvent
pH Acid a. dissociates into positively charged H+ and negatively charged ions b. HNO 3 and H 2 SO 4 Base a. dissociates into negatively charged OH- ions and positively charged ions b. NaOH
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 1 st Law of Thermodynamics a. “energy is neither created nor destroyed” 2 nd 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