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 -)