Systems, Matter, & Energy Chapter 2 Friday, August 14 th, 2015
Chapter Overview Questions What are major components and behaviors of complex systems? What are the basic forms of matter, and what makes matter useful as a resource? What types of changes can matter undergo and what scientific law governs matter? How are the scientific laws governing changes of matter from one form to another related to resource use, environmental degradation and sustainability?
Systems Systems: set of interacting components connected in such a way that a change in one part affects 1+ other parts of the system The earth is the largest system that environmental science looks at
The Effects of water diversion on Lake Mono
Matter Nature s Building Blocks; anything that has mass and takes up space Types of Matter: elements single type of atoms, cannot be broken down into other substances 92 natural +18 synthesized compounds - 2 or more different elements, held together by chemical bonds (fixed proportions) ex: H 2 O
Elements Important to the Study of Environmental Science
8 elements make up 98.5% of the Earth s crust
Compounds Important to the Study of Environmental Science
Building Blocks Atoms smallest unit of matter Elements Composed of atoms, cannot be broken into simpler components Atomic theory: all elements made up of atoms Molecules Two or more atoms of the same or different elements held together by chemical bonds ex: H 2, O 2, N 2
Basic Chemistry Terms Atomic Number - # of protons Subatomic particles Protons (p + ) with positive charge and neutrons (n 0 ) with no charge in nucleus Negatively charged electrons (e - ) orbit the nucleus Mass Number protons (p + ) + neutrons(n 0 )
Basic Chemistry Terms
Atoms, Ions, and Molecules Are the Building Blocks of Matter Ions- electrically charged atom or combination of atoms Metals: lose e - Nonmetals: gain e - ph Measure of acidity Neutral = 7 Acid(H + ions) = 1-6 Base (OH - ions) = 8-14
Ions Important to the Study of Environmental Science
Ions Important to the Study of Environmental Science
Isotopes Elements with same atomic number but a different mass # (C 12, C 13 & C 14 )
Atoms, Ions, and Molecules Are the Building Blocks of Matter Ionic bonds - gaining/losing electrons made up of opposite charged ions Na + Cl - (the charge imbalance holds them together) Covalent bonds - sharing electrons uncharged atoms methane: CH 4 Chemical formula type of short hand to show the type and # of atoms/ions in a compound. Ex. NaCl or CH 4
Atoms, Ions, and Molecules Are the Building Blocks of Matter
Atoms, Ions, and Molecules Are the Building Blocks of Matter Hydrogen bond- covalently bonded H atoms are attracted to another atom on a different molecule (weaker than ionic and covalent bonds) Polar bond- unequal sharing of electrons One side becomes slightly positively charged, the other slightly negative
Brain Break: Review Relay Each team will get a list of questions to answer. Each question must be answered in order & one at a time. Run up to Miss Scott, get your answer checked, and go back to your table to answer the next question. You must run around the room and back to your table Each team member must take a turn coming up to get the answer checked.
Organic Compounds Contain carbon and hydrogen Hydrocarbons C 8 H 18 gasoline and chlorinated hydrocarbons C 14 H 9 Cl 5 DDT Simple carbohydrates C 6 H 12 O 6 Macromolecules: complex organic molecules
Organic Compounds: Macromolecules Carbohydrates C, H and O used as quick energy source Made up of monosaccharides (glucose) Proteins Used for structural support, transport, defense and as enzymes (control rate of chemical reactions) Made up of amino acids (nitrogen containing organic molecules)
Organic Compounds: Macromolecules Nucleic Acids Found in all living cells Lipids DNA: genetic material RNA: used to synthesize proteins Used for long-term energy storage (fats) Make up membranes Do not mix with water
Inorganic Compounds No carbon to carbon or carbon to hydrogen bonding, not originating from a living source Earth s crust minerals, water Water, nitrous oxide, nitric oxide, carbon monoxide, carbon dioxide, sodium chloride, ammonia
Matter Occurs in Various Physical Forms Solid Liquid Gas High-quality matter Low-quality matter
Matter Quality: High or Low A measure of how useful matter is for humans based on availability and concentration.
Matter Undergoes Physical, Chemical, and Nuclear Changes Physical change - chemical composition not changed ex: ice melts Chemical change - chemical composition has changed Nuclear change Natural radioactive decay Radioisotopes: unstable Nuclear fission (split apart) Nuclear fusion (fuse together)
Nuclear Changes Nuclei of certain isotopes are unstable so they are radioactive. Radioactive isotopes undergo radioactive decay, spontaneous release of material from the nucleus Changes radioactive element into a different element
Radioactive decay Radioactive isotope Alpha particle (helium-4 nucleus) Gamma rays Beta particle (electron) Nuclear fission Uranium-235 Fission fragment Energy Nuclear fusion Fuel Proton Neutron Hydrogen-2 (deuterium nucleus) Reaction conditions 100 million C Products Helium-4 nucleus Energy Neutron Uranium-235 n Energy n Fission fragment n Energy Energy n n n Hydrogen-3 (tritium nucleus) Neutron
Half - Life Time needed for one-half of the nuclei in a radioactive isotope to decay and emit their radiation. Signficance: Some elements emit harmful radiation (so we can know how long it s dangerous for if we know it s half-life).
Carbon Dating Carbon-14 is radioactive and it s half-life is 5370 years. Organisms incorporate carbon into their tissues at ~atmospheric ratio (When it dies, stops incorporating & C inside starts to decay) Can measure the proportion of C-14 and determine how many years ago the organism died.
Chemical Reactions Molecules separate into atoms and recombine ** notice same number of atoms of each element on each side
We Cannot Create or Destroy Matter Law of conservation of matter no atoms are created/destroyed during a physical or chemical change. Matter consumption Matter is converted from one form to another
Energy Flows & Matter Cycles Matter is neither created nor destroyed, it just changes form and cycles throughout the system (our earth).