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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 |