Midterm Flashcards
Kilo
x103
Hecta
x102
Deca
x10
Deci
x10-1
Centi
x10-2
Mili
x10-3
element
the simplest form of matter that has unique properties (a kind of atom)
pure substance
compound
2 or more elements chemically bonded together in a fixed proportion (can be broken)
pure substance
mixture
2 or more substances combined physically, not chemically
homogenous mix/solution
a mixture that has uniformly distributed components where every sample is the same
can be solid, liquid, gas, aqueous
impure substance
heterogeneous mix
a mixture with distinct phases or layers (good for separation of mixtures)
impure substance
Experimental Errors
Leaks/Spills
“System”: the way the reaction is conducted
Systematic Error
design flaw
not cleaning out beaker/flask/container thoroughly
uncalibrated scale
sig figs
way to measure precision of your tools
the # of digits that are not placeholder zeros/the #s recovered from your measurement
precision
represents the repeatability of a measurement
recorded in sig figs
technique impacts precision
accuracy
how representative the measurement is of what you actually want
measured by % error: |actual - accepted|
——————- x100%
accepted
tools and estimation impact accuracy
adding/subtracting sig figs
1) count sig figs to the right of the decimal in each measurement
2) use the lowest number
multiplying/dividing sig figs
1) count sig figs in each measurement
2) use lowest number
Aristotle
thought: things can be split indefinitely
Democritus
thought: there is a limit to the amount something can be split
Dalton
found that gases react in multiples of 22.4 L
found that everything reacts in simple whole # ratios (Law of Multiple Proportions)
found that compounds combine in non-varying ratios, a different ratio means a difference compound (Law of Simple Proportions)
Thompson
plum pudding model
no nucleus or empty space
neg particles can move around freely (Crookes Tube) ===> permiable, squishy outer layer
Rutherford
found the nucleus and empty space in the atom
fixed the electrons into orbits (that forced them to go faster than the speed of light)
shot alpha particles at a piece of thin gold leaf and some of the alpha particles deflected elsewhere ===> there is a hard, dense, positive nucleus, but mostly empty space
Bohr
thought that electrons existed in different energy levels (if they couldn’t possibly orbit as Rutherford suggested), but still orbit in those energy shells
he had no reason why this would happen
de Broglie
found out that electron are waves, so they have to exist in different energy levels
thought that all materials are wavelike
things like baseballs are too large to be wavelike
electroscope
proved there are two charges
isotopes
same element, but different masses (different number of nuetrons)
atomic mass
of neutrons + protons
atomic number
of protons
chemical formulae
a symbolic system of letters and numbers that precisely and accurately tells the chemical makeup of a compound
formula mass
sum of the atomic masses of every atom in the compound
molar mass
the formula mass, but each amu is a gram
number of moles
mass given
molar mass
percent mass
mass of what you want
————————————- x100%
total mass
atomic structure
hard, dense, + nucleus in the center surrounded by energy levels of subshells or a set number of orbitals, which contain 2 electrons each
electron configuration
coordinates for the electrons of an element in its ground state
molecular formula
C6H12O6
formula mass
—————————— x empirical formula
empirical formula mass
empirical formula
the whole # ratio of the atoms in the compound
polarity
uneven electron distribution (either in a bond or a compound)
dipole
polar
Intramolecular Forces
forces inside molecules (Bonds)
Intermolecular Forces
attractive forces between molecules (IMF) that hold substances together (+ attracted to -)
Ion-Dipole Forces (IMF)
polar molcules attracted to an ion (the ion is atracted to the oppositely charged side of the polar molecule)
Hydrogen Bond
(not really a bond) hydrogen bonded to an electronegative element (F, Cl, O, S)
Dipole-Dipole Forces
2 or more polar molecules with IMF (+ attracted to -)
Dispersion
2 or more nonpolar molecules bump occasionally, which causes a momentary polarity. (the bigger the molecule and more surface areas means more IMF)
metallic bonding
metal + metal
a group of metal atoms self-ionizes and loses its electrons into a general delocalized pool or bonding electrons
bendy and conducts heat
isomers
2 or more structures with the same formula, but different structures
bond
association between 2 or more atoms that stabilizes both atoms, which causes them to stick together
ionic
transter of electrons from the least electronegative atom to the more electronegative atom
EN > 1.7
w/ metal
electronegativity
an atom’s pull on an electron
increases to the right: more protons
decreases down: more energy levels, so the electrons are further out
tells the polarity of a molecule
delta EN = |ENatom1 - ENatom2|
covalent
2 or more atoms have overlapping orbitals, such that the electrons count for both atoms and they statisfy the octet rule (pairs of electrons are shared)
EN ≥ 0.4 polar
EN < 0.4 nonpolar
w/o metal
formal charge
valence electrons - assigned electrons
you want it to be 0
Lewis Dot Structure
drawings that represent molecules
1) element symbol represents the atom w/o valence electrons
2) dots represent the valence electrons
VSEPR Theory
Valence Shell Electron Pair Repulsion
electron shells will orbit themselves in such a way as to minimize repulsion
shapes
NH4+1
ammounium
OH-1
hydroxide
CO3-2
carbonate
PO4-3
phosphate
SO4-2
sulfate
NO3-1
nitrate
C2H3O2-1
acetate
ammounium
NH4+1
hydroxide
OH-1
carbonate
CO3-2
phosphate
PO4-3
sulfate
SO4-2
nitrate
NO3-1
acetate
C2H3O2-1
Binary Ionic Compounds Naming
1) write the + ion
2) write the - ion, drop the last syllable and write “-ide”
2 nonmetals bond naming
1) write least electronegative
2) write most electronegative
3) add # prefix
1-mono, 2-di, 3-tri, 4-tetra, 5-penta, 6-hexa, 7-septa, 8-octa
limiting reactant
reactant that will run out first
Crystallization
heat
separate by melting/boiling point
solid-liquid, liquid-liquid solutions
Centrifuge/Separatory Funnel
separate by density
Filtration
separate by size
solid-liquid
Attraction/Mechanical
separate by force-experiencing mixtures
solid-liquid, solid-solid, solid-gas
Distillation
heat until one part changes state, condense then separate
gas-gas, liquid-liquid solution
Chromatography
separate by adhesion/solubility
octet rule
atoms want 8 electrons (full s and p)
valence electrons
highest n value
quantum numbers
numerical values that represent unique electrons
n = energy level
l = subshell (s=0, p=1, d=2, f=3)
m = orbitals (-l to l)
s = spin up/spin down (1/2 or -1/2)
excited state
an electron in a higher shell than it should be
UV transition
to and from n = 1
Visible transition
to and from n = 2
IR transition
any other transition
Blackbody Radiation
energy given off by an object because it is heated, objects should go through the colors (ultimately get bluer) as it gets hotter, but it doesn’t
Zeff/ENC
proton’s pull on electrons - nonvalence electrons
how protons are negatively effected by the nonvalence electrons
increases right: more protons
decreases down: nonvalence electrons increase faster than protons
atomic radius
1/2 the distance between the center of 2 adjacent atoms
decreases right: same number of shells of electrons and more protons
increases down: more physical size is added (protons, neutrons, electrons)
ionization energy
energy needed to remove one electron from a neutral atom
increase right: get closer to noble gas configuration, don’t want to get rid of their electrons
decrease down: there is more distance bewteen the electrons and protons
ionic radi
size of the atom as its most stable ion
+ ions = smaller b/c you lose electrons
- ions = bigger b/c you add electrons
Net Ionic Equations
equation showing the ions involved in the chemical reaction
stoichiometry
Synthesis
element + element —> compound
stoichiometry
Decomposition
compound —-> element + element
stoichiometry
Single Replacement
A+B- + C+ —–> C+B- + A+
stoichiometry
Combustion
H?C? + O2 —–> CO2 + H2O
stoichiometry
Double Replacement
A+B- + C+D- —–> A+D- + C+B-
Mega
x106
Micro
x10-6
Nano
x10-9
Pico
x10-12
Quantum Mechanical Model
explains orbits based on the electron wave interference
metallic character
ability to lose electrons
decrease right: close to noble gas configuration
increase down: pull of protons is less because more energy levels
metals
lower electronegativity
lose electrons easily
conduct electricity and heat
bendy/malleable
nonmetals
gain or share electrons easily
higher electronegativities
brittle
metalloids
have properties of metals and nonmetals
