Physical Science Exam 3 Study Guide PDF

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Study guide and summary for material on exam 3. Very comprehensive. ...

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Chapter 18 1. reversible and irreversible processes a. reversible: can be reversed, relatively rare in nature- only very special circumstances, can go BOTH ways at the SAME TIME (forward and backward.) b. irreversible: very common (practically all), only go one way, they must be forced to go the other way (with extra energy). example-ice cubes melting in the sun. 2. order and disorder, entropy a. the natural state of the world is disorder-it will keep becoming more and more disorderly as time goes on. b. entropy: the amount of disorder in a system. c. solids have low entropy and little microscopic kinetic energy, liquids have medium entropy and slightly more microscopic kinetic energy, and gases have high entropy, and the most microscopic kinetic energy. d. Entropy of universe(stay same or go up always)= entropy system( down) + entropy of surroundings (up) 3. law of increasing disorder (2nd law of thermodynamics) a. a reversible process does not change the total amount of disorder in the universe. an irreversible process increases the total amount of disorder in the universe. b. this says that we must consider the total  entropy of the universe. (figure 18.7, pg. 224) 4. ranking of energy forms and application to specific processes (refrigerator, fuel engine) Chapter 19 1. five types of matter ● Solid ● Liquid ● Gas ● Plasma ● Don’t know, need to look in book. Condensates? State of matter changes as you add more energy. 2. three types of structural organization of matter ● Atoms- Single atom eg. Helium ● Molecules- Multiple atoms bonded together into discrete tiny particles eg. H2O ● Networks-Multiple atoms bonded together into network like like structures. (Strongest) 3. chemical formulas and representations of molecules 4. molecular models 5. geometry of molecules 6. instrumental techniques (infrared absorption spectroscopy and mass spectrometry) Chapter 20 1. Chemical bonding

2. chemical reactions (reactants, products) and balancing chemical equations 3. rates of reactions figures (20.4 and 20.7) 4. energy and entropy changes during chemical reactions for system and environment 5. catalysts 6. equilibrium Chapter 21 1. Metallic bonding, band structure, properties of metals and alloys Metallic bonding- between metal + metal Band structure- Partially filled bands lead to: the “metallic bond” (Delocalized electrons (sea) malleability, easy energy jumps-opacity and reflectivity, good mobility-thermal and electrical conduction, strong binding of atoms-high melting and boiling points, the quantum model explains it all. Lots of atoms share lots of electrons: metals • Nonmetals “take” electrons from metals: ionic materials • Nonmetals share electrons with each other: covalent materials 2. explanation of these properties from bonding mechanism 3. metals vs. semiconductors Semiconductors have more valence electrons compared to metals. Semiconductors.. band gaps. Bigger jump more blue. Smaller jump more red. 4. LEDs Chapter 22 1. Ionic bonding, properties of ionic compounds Bond between metal+nonmetal Properties- high melting & boiling points. Very strong, a lot of energy is needed to break them. 2. explanation of these properties from bonding mechanisms Chapter 23 1. Covalent bonding, properties of covalent substances Bond between nonmetal + nonmetal Properties- Low melting and boiling points, soft or brittle solid forms, poor electrical and thermal conductivity. They exist as molecules rather than as extended networks. May exist as solid, liquid, or gas. Poor conductors of heat. 2. explanation of these substances from bonding mechanism They fill their valence shells. They end up sharing some of their electrons. They can share more than two electrons, BUT… they do not always share electrons equally. Example: Slide 5. 3. electronegativity, polarity of bonds, polarity of molecules 4. intermolecular forces How molecules stick together! “Weak” but critical: determine melting and boiling points, properties of water (life). Hydrogen bonds (H bonded to N, O, or F) are the strongest. Permanent dipoles for polar molecules leads to dipole-dipole forces. Dispersion forces for non permanent dipoles eg. between N2 molecules. Chapter 24

1. fats vs. oils Fats- solid at room temperature. Ex- butter, shortening, lard. Oils- liquid at room temperature. Ex- olive oil, canola oil, vegetable oil Oils and Fats at room temperature (+15 degrees C) 2. saturated vs. unsaturated fatty acids Differ in how they bond with hydrogen. Double bonds are found in unsaturated fatty acids Unsaturated fatty acids have kinks 3. silicate fibers, sheets, and chunks Chapter 25 1. the nuclear forces 2. average nuclear mass 3. radioactive decay Spontaneous. Individual decay events happen randomly. Statistics ruled by half-life (the time it takes for half of the nuclei to decay) Like double-slit, particle wave duality. 4. fission vs. fusion Fusion- small nuclei assemble and form a larger one and the average nucleon mass drops. Fission- Nuclei split such that the average mass per nucleon goes down. With fission large nuclei disintegrate into smaller ones and the average nucleon mass drops....