| chemical reaction | change from reactants to products; rearrangement of bonds between atoms |
| mixture | blend of 2 or more substances |
| homogeneous mixture | uniform composition; same throughout; "one phase" |
| heterogeneous | not uniform composition; 2 or more phases |
| element | simplest form of matter |
| law of conservation of mass | matter cannot be created nor destroyed (it can be rearranged to form new bonds) |
| observation | observe with senses |
| interpretation | judgment about an observation |
| compound | 2 or more elements chemically combined that can only be separated with a chemical reaction |
| error | accepted value - experimental value |
| percent error | (absolute value of error/accepted value) x 100% |
| accuracy | how close a measurement is to the "true" value |
| precision | how close a set of measurements is to each other |
| density | mass/volume |
| specific gravity | compares density of substance to density of a reference substance |
| density of water | 1g or 1 mL |
| absolute zero | 0 K, or -273 degrees celcius; all molecular motion stops |
| mole | 6.02 x 10^23 representative particles/mole |
| molar mass | the mass of one mole of any substance; atomic mass in grams |
| 22.4 L | 1 mole of any gas at STP |
| standard temperature and pressure | STP |
| percent mass | (mass of element in compound/molar mass of compound) x 100% |
| empirical formula | lower whole number ratio of atoms of the elements in a compound |
| molecular formula | "real" formula; same as or some whole number multiple of the empirical formula |
| OKAY! | KNOW HOW TO CALCULATE EMPIRICAL/MOLECULAR FORMULA. OKAY?! |
| combination reaction | 2 things combine to form 1 thing |
| decomposition reaction | 1 thing turns into 2 things |
| single replacement reaction | element + compound turns into new compound + element |
| double replacement reaction | rxn where given 2 compounds, cations trade places |
| combustion reaction | rxn that involves burning something in oxygen |
| hydrocarbon | CHO |
| isotope | atoms with differing numbers of neutrons; differing masses |
| alpha particle | helium particle; decreases atomic number by 2, mass by 4, neutrons by 2 |
| beta particle | converts neutrons into protons; increases atomic number by 1; no mass; decreases neutrons by 1 |
| positron | converts protons into neutrons; decreases atomic number by 1; no mass; increases number of neutrons by 1 |
| gamma radiation | usually emitted w/ alpha + beta particles; electromagnetic radiation; no mass, no charge=no change in mass when emitted |
| alpha emission | radiation: cannot penetrate dead skin, paper; can penetrate soft tissue |
| beta emission | radiation: can be stopped by wood/aluminum foil |
| gamma emission | radiation: can be stopped by several inches of Pb or concrete |
| half-life | amount of time it takes for half the atoms of a radioactive isotope to decay to products |
| carbon dating | determining the age of objects using the ratio of C-12 to C-14 |
| transmutation | the conversion of one element into another |
| transuranium elements | elements with atomic numbers greater than 92; manmade; radioactive |
| fission reaction | the splitting of a nucleus |
| number of molecules; number of moles | what coefficients in chem rxns represent |
| limiting reactant | reactant that runs out (determines amount of product formed) |
| excess reactant | the reactant that is left over |
| percent yield | (actual yield/theoretical yield) x 100% |
| kinetic theory | theory: particles in all states of matter are in constant motion |
| kinetic energy | energy of motion |
| potential energy | stored energy (chemical energy) |
| elastic collision | energy is transferred totally from one particle to another |
| gas pressure | the force exerted by gas particles (in motion) hitting a body |
| pressure | force/area |
| vacuum | no particles (air) --> no force --> no pressure |
| atmospheric pressure | pressure caused by gas particles in air/atmosphere |
| barometer | measures atmospheric air pressure |
| 760 mm Hg; 101.3 kPa | 1 atmosphere |
| 1/2 mv^2 | kinetic energy formula |
| evaporation | a cooling process; molecules at a higher temperature leave to become gas, cooler particles left over |
| perspiration | sweating |
| vapor pressure | pressure due to the gas above the liquid |
| boiling point | when vapor pressure = atmospheric pressure |
| melting point | temp at which a solid melts and becomes a liquid |
| unit cell | smallest group of particles within a crystal which retains the geometric shape of the crystal |
| allotrope | different molecular forms of the same element in the same physical state |
| amorphous solids | solids which lack an ordered internal structure (rubber, glass) |
| crystalline solid | have orderly arrangement of atoms, ions, molecules that make up the solid |
| critical point | liquid and gas indistinguishable (super critical fluid) |
| triple point | where all three phases coexist |
| thermochemistry | the study of heat changes that occur during a reaction |
| energy | the capacity to do work or the ability to supply heat |
| heat | energy that is transferred from one substance to another due to temperature differences; can't measure it directly (only its effects) |
| thermoequilibrium | heat stops moving; heat moves from hot to cold until the temps are equal |
| positive q value | heat flows into system; heat is absorbed; "endothermic"; takes in heat; feels cold |
| negative q value | heat flowing out of system; heat released; "exothermic"; feels warm |
| law of conservation of energy | energy cannot be created nor destroyed |
| Calorie | amount of energy required to raise 1g water 1degree Celcius |
| specific heat | amount of energy required to raise 1g of a SUBSTANCE 1 degree celcius |
| Q = CMAT | Q=CMAT |
| heat capacity | amount of energy (heat) required to raise temp of a specific OBJECT |
| specific heat x mass of a substance | equation for heat capacity |
| hess' law | if 2 or more chemical rxns combine to give a final equation then you can add the deltaH values to get the final deltaH |
| democritus | coined "atom" |
| dalton's atomic theory | all elements composed of atoms; diff properties of diff elements can be explained by fact that diff atoms are fundamentally diff; each element made from 1 kind of atom; atoms of diff elements combine in whole number ratios to form compounds; chem rxns change how atoms bonded to each other |
| atom | smallest particle of an element that retains properties of that element |
| jj thomson | discovered electron; cathode ray tube; plum pudding model |
| millikan | oil drop experiment: determined exact charge of electron; found mass of electron = 1/1840 mass of H atom |
| golstein | discovered proton |
| chadwick | discovered neutron |
| 1 | mass of proton; mass of neutron |
| rutherford | discovered nucleus; bombarded gold foil with pos alpha particles |
| (% abundance) x (mass of 1 isotope) + (% abundance) x (mass of 1 isotope) | average atomic mass |
| dmitri mendeleev | developed periodic table (arranged elements by mass, similar properties) |
| mosely | arranged elements by atomic number |
| periodic law | certain properties of elements repeat periodically when arranged by atomic number |
| neils bohr | planetary model: electrons move in fixed paths aroun nucleus, have fixed energy |
| schrodinger | wrote mathematical equation for location of electron; based on probability |
| energy levels | areas around nucleus where electrons most likely to be found |
| aufbau principle | electron enters orbitals with lower energy first |
| pauli exclusion principle | orbitals may hold at most two electrons; must have opposite spins |
| hund's rule | electrons going into orbitals w/ same energy fill one electron per orbital all with same spins |
| isoelectronic | having the same electron configuration |
| electromagnetic radiation | energy; travels in waves; visible light is a small section of spectrum |
| lambda | symbol for wavelength |
| nu | symbol for frequency |
| 3.0 x 10^8 m/s | speed of light = c = speed of electromagnetic radiation in a vacuum |
| planck | scientist who related energy of a wave to its frequency |
| E = h x nu | planck's constant where h = 6.62 x 10^-34 |
| photon | light quanta |
| photoelectric effect | shine light on metal to observe effects |
| frequency | color |
| amplitude | brightness |
| lambda = h/mv | debroglie equation |
| heisenberg uncertainty principle | can't know an object's position and motion at the same time |
| shielding effect | electrons closer to nucleus shield outer electrons from nuclear pull |
| molecular compound | electrons shared; 2 non-metals; low melting/boiling points; liquid or gas at room temp |
| ionic compound | electrostatic attraction; metal + nonmetal; high melting/boiling points; crystalline solids at room temp |
| binary compound | compound ending in -ide; only has 2 elements in it |
| polyatomic ions | tightly bound groups of atoms that behave as a unit and carry a charge |
| representative unit | formula unit (like a "molecule) |
| metallic bond | attraction of valence electron for positively charge metal ion; bond b/t 2 metals |
| alloy | mixture of 2 or more elements, one of which is a metal |