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Chapter 2 : Matter
| Term | Definition |
|---|---|
| Matter | anything that takes up space (volume) and has mass |
| physical properties | no change in the composition of matter |
| chemical properties | how matter changes in the presence of other matter |
| rust | chemical property |
| color, shape, density | physical properties |
| odor, taste, conductivity | physical properties |
| melting, freezing, condensing, and vaporizing | physical changes |
| digesting something, burning, rotting | chemical changes |
| pure substances | consist of one TYPE of matter |
| cannot be separated into other kinds of matter by physical means | pure substances |
| elements | made of atoms |
| cannot be broken down into simpler substances by ordinary chemical means | elements |
| two or more ELEMENTS chemically BOUND together | compounds |
| Cu, N2, H2 | elements |
| CO2, C6H12O6, NaCl | compounds |
| can be separated by physical means into two or more pure substances | mixtures |
| Homogeneous Mixtures | show only one place or appearance throughout a.k.a. solutions |
| sugar water, air, salt water, cola | homogeneous mixtures |
| Heterogeneous Mixtures | have distinct regions called PHASES |
| Granite & Italian dressing | heterogeneous mixtures |
| an element whose atoms do not combine with other atoms | monatomic elements |
| name the Monatomic Elements | Neon, helium, argon, xenon |
| an element whose atoms bond into two-atom units | diatomic elements |
| name the diatomic elements | Hydrogen, nitrogen, oxygen, florine, chlorine, bromine, iodine |
| elements whose atoms bond into multi-atom units | polyatomic elements |
| energy | the ability to do WORK; related to the force that matter generates and the resulting actions of that force |
| mechanical energy | possessed by objects that are moving (kinetic energy) or have the potential to move (potential energy) |
| thermal energy | heat energy |
| sound/acoustic energy | particles move in a periodic way like waves |
| electrical energy | movement of charged particles |
| radiant energy | radiates out from the sun |
| wind energy | from the wind |
| electromagnetic energy | from the sun |
| nuclear energy | from the nucleus of an atom |
| chemical energy | stored in chemical bonds |
| exothermic reactions | release energy and feel hot to the touch |
| endothermic reactions | absorb energy and feel cold |
| vibrations from a loud speaker | sound energy |
| a pot of near boiling water | thermal energy |
| a camera flash | electromagnetic energy |
| the source of an explosion of dynamite | chemical energy |
| changes occurring at the center of a star | nuclear energy |
| a rolling ball | mechanical energy |
| thermodynamics | the study of the flow of energy, the movement and conversion of energy |
| Law of Energy Conservation | energy can neither be created nor destroyed only changed from one form to another |
| the first law of thermodynamics | matter and energy can neither be created or destroyed only changed from one form to another (E=mc2) |
| Second Law of Thermodynamics | during energy transformations, some enerrgy changes to an UNUSABLE form --> going from order to disorder --> increase entropy |
| Entropy | the measure of DISORDER or randomness in a system --> entropy INCREASES over time |
| Diffusion | evenly spreading out particles over time through motion |
| drop of food coloring in a beaker | diffusion |
| HIGHER concentration of area to LOWER concentration | diffusion |
| Kinetic energy | energy of motion; particles are in CONSTANT motion |
| depends on both the mass of an object and its velocity | kinetic energy |
| Total Energy | kinetic energy + potential energy |
| Temperature | the AVERAGE KE of a system's particles; not related to the number of particles but how much the AVERAGE is per particle |
| Thermal Energy | the sum of the KE of an object's particles; IS related to the number of particles; more particles = more energy |
| flows from hot to cold | thermal energy |
| the transfer of thermal energy (heat) between two objects | heat transfer |
| unit for energy | Joule (J) |
| BTU | British Thermal Unit - amount of heat required to raise the temperature of 1 pound of water to 1 degree F |
| calorie (cal) | the amount of energy required to raise the temperature of 1 gram of water to 1 degree Celsius |
| kilocalorie (C) | 1 000 calories -- used to measure energy in food |
| Celsius scale | freezing point of water: 0 boiling point of water: 100 |
| Kelvin Scale | freezing point: 273 boiling point: 373 |
| absolute zero | the point (0K) at which ALL molecular motion stops completely -- has never been reached |
| Third Law of Thermodynamics | it is IMPOSSIBLE to reach absolute zero |
| Kinetic Molecular Theory | - all matter is made of microscopic particles that are in constant motion - if you add energy to the particles they will speed up - atoms, molecules, and ions are attracted to each other by electrical forces keeping them from flying apart |
| Solids | have little energy compared to the attractive forces between the particles, but the particles still vibrate |
| attractive forces OVERPOWER the KE of the particles | solids |
| particles are in fixed positions or shape | solids |
| in-compressible | atoms resist being squeezed together more; solids |
| the particles have more energy than a solid but the attractive forces still hold the particles together | liquids |
| have limited motion and the ability to FLow they are FLuids | liquids |
| near in-compressible because the atoms are already close together | liquids |
| DO NOT have a fixed shape, but change to fit container | liquids |
| high KE | gases |
| move to FILL container through diffusion | gases |
| no fixed position or shape | gases |
| highly compressible | gases |
| particles FLOW because they are FLUIDS | gases |
| most common state of matter | plasma |
| condensation | gas to liquid |
| vaporization | liquid to gas |
| freezing | liquid to solid |
| melting | solid to liquid |
| sublimation | solid to gas (DRY ICE) |
| deposition | gas to solid |
| the melting point is identical to the freezing point of a substance | TRUE |
| thermal energy, unlike internal energy, does not account for the potential energies of the particles in a system | TRUE |
| a chemical property of a substance cannot be determined without causing or attempting to cause a chemical change to occur in the substance | TRUE |