Question | Answer |
manipulated variable | variable that changes |
responding variable | variable that is observed as the result of an experiment |
scientific method | observe, hypothesize, predict, experiment |
matter | anything that has mass and takes up space |
chemical change | creating a new substance by changing the composition, irreversible |
physical change | properties of materials change but composition does not |
chemical reaction | reactants yield product |
compound | 2 or more elements chemically combined in fixed proportions |
element | purest form of matter, made of 1 substance |
reactant | substance that undergo a chemical reaction |
product | result of a chemical reaction |
heterogeneous | mixture of 2 or more substances that are not uniform |
homogeneous | 2 or more substances uniformly mixed |
law of conservation of mass | mass can not be created of destroyed |
precipitate | solid formed from 2 aqueous reactants in a chemical reaction |
vapor | gaseous state of substance that is a liquid of solid at room temperature |
accuracy | how close to the expected value |
conversion factor | ratio of equivalent measurements |
dimensional analysis | use of conversion factors to solve problems |
percent error | % error=|accepted-experimented|/accepted*100 |
precision | how close measurements are to each other |
scientific notation | a base number times a power of 10 |
significant figures | accurate measurements by the right number of digits |
atom | smallest part of matter that still holds all properties of an element |
atomic mass | weighted average of all isotopes of that atom |
atomic number | number of protons |
electrons | negatively charges, JJ Thompson |
proton | positively charged, Goldstein |
nucleus | protons + neutrons, center of atom |
group | up and down periodic table |
period | left and right of periodic table |
isotope | same number of protons but different number of neutrons |
mass number | protons + neutrons |
neutron | no charge, Rutherford |
atomic orbital | 1s, 3p, 5d, 7f |
atomic sublevels | s,p,d,f |
aufbau's principle | electrons enter orbitals in the lowest energy level |
electron configuration | 1s22s23p6 . . . |
energy levels | quantum number, n=1, 2, 3, 4 . . . |
ground state | electron is in the lowest energy level possible |
hund's rule | electrons enter orbitals with up spin then go back and fill up with down spin |
pauli exclusion principle | each orbital holds 2 electrons with opposite spins |
anion | nonmetals, receive electrons, negatively charged ion |
cation | metals, give away electrons, positively charged ion |
periodic law | along a period elements have similar properties |
atomic radius | distance between 2 nuclei of the same element |
electronegativity (electron affinity) | ability to attract an electron |
ionization energy | amount of energy it takes to remove an electron |
metalloids | along the staircase and has both properties of metals and nonmetals |
metals | left of staircase, good conductor, malleable, strong |
transition metals | groups 1b to 8b |
representative elements | groups 1a to 8a, short form |
nonmetals | right of staircase, not good conductors, mostly gases, brittle |
chemical formula | use symbols to show element and the number of each in a ionic compound |
electron dot structure | element symbol surrounded by dots representing valence electrons |
formula unit | another name for ionic compound |
ionic bond | transfer of electrons from cation to anion |
ionic compound | made up of metal cations and nonmetal anions |
metallic bond | formed by attraction of free flowing valence electrons for positively charged metal ions, "sea of electrons" |
octet rule | all elements want stable electron configuration like noble gases |
valance electrons | electrons in the outer most shell |
covalent bond | bonding of 2 or more nonmetals |
diatomic molecule | H2, N2. O2, F2, Cl2, Br2, I2, nonmetals that bonds with itself |
molecule | covalent compound |
nonpolar | covalent bond where atoms have equal pull (0-.4) |
polar | covalent bond in which electron are being pulled towards one atom over another (ex. H2O mickey mouse shaped) |
pi bond | double bond, 2nd bond formed |
sigma bond | single bond, 1st bond formed |
polyatomic ion | covalent compound with charge |
resonance | write 2 or more different lewis structures for the same compound |
unshared pair electrons | lone electrons not active in bond |
VSEPR theory | repulsion between lone electrons causes shape to bend |
structural formula | lewis structure with dots and dashes |
acids | H+ in front |
bases | OH- at the end |
binary compound | 2 elements bonded together either ionic or covalent |
monatomic ion | single element with charge |
law of definite proportions | chemical compounds have the same composition despite sample size |
law of multiple proportions | elements combine in whole number rations not decimals |
avagadro's number | 6.02*10^23 |
empirical formula | smallest ratio of a molecular formula |
molar mass | mass of 1 mole on an element or compound |
percent composition | % composition = (mass of element/mass of compound)*100 |
representative particles | atom, molecule, formula unit |
activity series | ability of an element to replace another in a single replacement |
balanced equation | has coefficients |
chemical equations | uses symbols for reactants and products, separated by ----> |
catalyst | speeds up chemical reaction but not involved |
synthesis/combination | A+B--->AB |
combustion | A+O2--->CO2+H20+heat |
decomposition | AB--->A+B |
single replacement | A+BC--->B+AC |
double replacement | AB+CD--->AD+CB |
skeleton equation | no coefficients |
spectator ion | not involved in net ionic equations |
actual yield | what it actually produces |
excess reagent | left over after chemical reaction |
limiting reagents | used up in chemical reaction, determines the amount of product produced |
mole ration | obtained by coefficients in balance equation |
percent yield | (actual/theoretical)*100 |
stoichiometry | calculating quantities from info provided in balanced equation |
theoretical yield | what it should produce, have to figure it out using mole island and not given |
measure the level of lead in the blood | analytical chemistry |
study non carbon based chemicals in rocks | inorganic chemistry |
investigate changes that occur as food is digested in the stomach | biochemistry |
study of carbon based chemicals in coal | organic chemistry |
explain the energy transfer that occurs when ice melts | physical chemistry |
what is density of water? | 1 g/mL = 1 g/cm3 |
why is an atom positively charged when it loses an electron? | more protons than electrons |
why is an atom electrically neutral | same number of protons and electrons |
name 2 ways that isotopes of the same element differ | number of neutrons and mass |
how many orbitals are in 2p energy level? | 3 |
how many sublevels are in the n=1 principle energy level? n=4 energy level | 1(s), 4(s, p, d, f) |
what is the max number of electrons that can go into the 3p sublevel? 4f sublevel? 3d sublevel? | 6,14,10 |
what are 2 ways an ion can form from an atom | gain of lose electrons |
compare the size of cations to its original element | cations are always smaller than the original element because it lost electrons |
compare the size of anions to its original element | anions are alway bigger because it gained electons |
why are ionic compounds chemically neutral? | charges on ions balance out |
what is the different between ionic bond and covalent bond? | ionic=transfer electrons covalent=share electrons |
what are the molecular shapes? | linear, bent, trigonal planar, trigonal pyramid, square planar, tetrahedral |
extensive properties | properties dependent on sample size (ex. mass, volume) |
intensive properties | properties that are not dependent on sample size but the type of matter (ex. density, color hardness, melting point, malleability) |
democritus | 1st to suggest idea of atoms, particles that were indestructable and indivisible, no evidence |
chadwick | neutron |
who used the gold foil experiment? to find what? | Rutherford used it to find the nucleus |
what were the curies responsible for | discovery of radioactivity |
Bohr's model | electrons orbit around nucleus in a fixed path, did not work for any atom than hydrogen |
electrons behave like _________. | waves of motion |
quantum | the amount of energy required to move an electron from one energy level to the next |
what happens when electrons get excited | electron gains energy and move up energy levels, when they return to ground state they emit light as result of electron transition |
bond dissociation energy | energy needed to break a bond |
van der waal forces (intermolecular forces) | dipole interactions, dispersion forces |
dipole | similar properties of an ionic or polar covalent bond but much weaker, 2 polar molecules are attracted to one another |
dispersion forces | momentary attraction of electrons due to the random motion of electron in an atom |