Question | Answer |
accuracy | measure of how close the measurement is to the "true"value |
precision | measure of how close together repeated measurements are to eachother |
volume | measure of how much three dimensional space a substance, especially gas or liquid occupies |
electrolytes | ions dissolved in water |
formula unit for ionic compounds | of an ionic compound represents the ration of cation to anion in the lattice |
formula mass for ionic compounds | sum of atomis masses of ions in formula unit (amu) |
molecular mass for covalent compounds | sum of atomic masses of atoms in molecular formula (amu) |
properties of nonmetals | -low melting point -hydrogen=nonmetal -own color -brittle -nonconductive -reduction |
element | substance somposed of only one type of atom, cannot be broken down into simpler form -109 known elements -90 unknown elements |
lattice structure | every cation is surrounded by anions; every anion surrounded by cations |
matter | anything that has maass and occupies volume |
momatomic ion | ion formed from a single atom |
diatomic molecules | molecules composed of two atoms |
molecular formula | a covalent compound that has definite & unique composition -gives limited info -doesnt indiciate arrangement of atoms or covalent bonds |
NH4 | ammoniun (cation) |
H3O | Hydronuim (cation) |
OH | hydroxide (anion) |
NO3 | nitrate(anion) |
CN | cyanide (anion) |
HCO3 | hydrogen carbonate (anion) |
HSO4 | hydrogen sulfate (anion) |
CO3 (2-) | carbonate ion (anion) |
PO4 (3-) | phosphate ion (anion) |
Guidelines for determining formula unit for ionic compound | 1. determine charge on cation 2. determine charge of anion (group #-8) 3.insert subscripts CA2+cl = CaCl2 4.divide by common divisor Mg2O2= MgO 5. Double check if neutral or not (cation charge x subscript) + anion charge x subscript) |
naming ionic compounds | -metal first, nonmetal second -take off ending add -ide to nonmetal -if multiple #, NaCl3; add the charge as roman numeral- Sodium (III0 Chloride -if compound has lower charge add-ous -if compound has higher chharge add- ic |
naming covalent compounds | prefixes 1-mono 2-di 3-tri 4-tetra 5-penta 6-hexa 7-hecta 8-oct 9-nona 10-deca ex: nitrogen oxide =NO nitrogen dioxide =NO2 |
polyatomic ions | ions made up of a group of atoms then a single atom |
allotrope | different forms of the element within the same phase -O2 & O3 -P- white; burns in air (r &b exist) Carbon - grahite, diamond, c60 (soccerball) |
density | physical property of mater often used to characterize a substance or material ... d=m/v |
properties of metals | -solids -metallic luster -malleability -ductile -conduct electricity -dense -oxidation |
covalent bonds | two nonmetals come together & share valence E -neutral -E are shared -2 or more nonmetals -discrete(individual) |
ionic compound | formed when a metal atom transfers some or all of its valence electrons to a nonmettal -cation/anion -metal and nonmetal -electrostatic -dimensional lattice of oppisitely charged atoms |
mass | measure of the amt of matter |
mass, location & charge of: P , E, & N | P= nuclues, positive, 1.6726x 10^-24 E= electron cloud, negative, 9.108 x10 ^-28 N=nuetral, nucleus, 1.750 x 10 ^24 |
average atomic mass | weighted average of the mass of its isoptopes based on their natural adundance |
calcuate average mass | avg=(%x100)(mass1) + (%x100)(mass2) |
ion | atom that has lost or gained one or more valence electrons -positive or negative |
compound | substance composed of two or more diff types of atoms held together in a unique proportion -broken down through chemical reactions |
nonbonding or lone pairs | electrons that dont share an electron |
ionic bond | electrostatic attraction that holds ions together |
ionization | process when metals lose electrons |
molar mass | mass of one mole of an element or comound |
pure substance | substance composed of only one compound or element |
change F to C | (f-32)5/9 |
Change C to F | 9/5(C + 32) |
Change C to K | add 273 |
Change K to C | -273 |
isotopes | atoms with the same number of protons but a different # of neutrons |
atoms | smallest particle that retains the properties of an element - atom is to element as molecule is to compound |
molecule | smallest particle retainnig properties of the compound, but, some elements exist as molecules in their stable form |
a-s=us | unshared atoms |
atomic number | # of protons an atom contains |
dimensional analysis | considers the units (dimensions) to set-up the calculation supplied x req/supplied = req |
chemical properties | refer to its behavior in the presence of other chemical substances -transorms substances into new substance |
every measurement consists of: | # & a unit |
nanoscale & atomic scale | describes matter too small to be seen even with a microscope |
scientific notation | used to express really small # or really big # |
SF: x & / | never give more SF in the answer than least # given |
SF: + & - | never give more after the decimal than the least number given after the decimal |
micronutrients | required in quanities of less than 100mg/day |
the mole | 6.02 x 10^23 aka avagrados number |
anion | # of electrons greater than the number of protons -neg charged -nonmetals gain electrons to becom anions |
cation | less than the number of protons -positively charged -metals lose electrons to becom cations |
electron orbital | region of space where electrons are found |
energy levels | lower the lectrons on the shells; lower the energy -three orbitals |
elements to the right of the periodic table... | gain electrons |
temperature | measure of the intensity of heat |
diatomic molecules found in nature | BrINClHOF bromine iodine nitrogen chlorine hydrogen oxygen flourine |
bohr model | thought electroms orbitied around the nucleus like planets around the sun |
electron configuration levels | 1s2 2s2 2p6 3s2 3p6 4s2 4p6 |
outershell & innershell electrons | outer- valence electrons inner- core lelectrons |
elements on the left of the periodic table.. | drop electrons |
heat | form of energy |
inert | unreactive |
octect rule | prediction of a molecule structure of a molecule by arranging electrons so that each atoom has a full outermost shell |
significant figures | all the certian digits as well as the one uncertian digit |
electrostatic attraction | "glue" that holds ions together - force of attraction btwn oppositely charged entities (cation & anion) |
physcial properties | properties we observe or measure without considering how the element interacts |
weight | weight depends on gravitational pull |
macronutrients | elements required in large quanities . more than 100mg/day |
lewis dot structure | represent a pair of bonding electrons with dots or lines |
mass number | sum of protons & neurons of the isotopes |
metric conversion | mathemetical transformation of a value in one metric unit (supplied unit) into another metric unit( requested unit) |
macroscopic scale | all material you can see |
covalance | how many bonds commonly found |
periodicity | property of elements in the same column ( similiar physical & chemical) |
margin of error | conveyed in the number of digits reported in the # -10lb -10.0lb -10.00lb |
valence electrons | # of electrons in the outermost shell of an atom -equal to group # |
N-A=S | n= # of E needed A= # of E available S= # of E shared |
microscopic scale | cannot be seen by the naked eye |
guidelines for sig figs | 1.nonzeros sig (3.45= 3SF) 2.Trap zeros are sig ( 3.05 =3 SF) 3. zeros following nonzero & decimal pt sig (0.400 = 3SF)(4.0 - 2 SF) 4. no decimal -zeros not sig (6,000 = 1 SF) 5. Zeros that appear before nonzeros not sig (0.00040 = 2 SF) 6. all # in SN |