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Colomac Semester One AP CHEM finals
cram session
52
Chemistry
11th Grade
01/24/2012

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Term
two fundamental concepts of chemistry
Definition
1. matter is composed of various types of atoms
2. one substance changes to another by reorganizing the way atoms are attached to each other
Term
natural law vs. theory
Definition
- natural law = summary of observed (measurable) behavior
- theory = attempt to explain behavior (why it happens)
Term
fundamental SI units: mass, length, time, temperature, amount of substance, volume, electric current, luminous intensity
Definition
kilogram (kg), meter (m), second (s), Kelvin (k), mole (mol), liter (L), ampere (A), candela (cd)
Term
mass vs. weight
Definition
- mass = measure of the resistance of an object to a change in its state of motion
- weight = force that gravity exerts on an object
Term
homogeneous vs. heterogeneous
Definition
- homogeneous = visibly INDISTINGUISHABLE parts --> solution
- heterogeneous = visibly DISTINGUISHABLE parts --> pure substance(constant composition) or 2+ solutions
Term
methods to seperate components into mixtures
Definition
1. distillation
2. filtration
3. chromatography = stationary phase (solid), mobile phase (liquid or gas)
4. paper chromatography = stationary phase is paper
Term
percent uncertainty
Definition
if given A±B(uncertainty),
percentage uncertainty = (B/A) x 100
Term
calculating uncertainty
1. adding/subtracting
2. mutiplication/division
3. to a power
Definition
1. absolute uncertainties can be added
2. convert absolute uncertainty to percent uncertainties, then add
3. percent uncertainty times the power
Term
What to do with sigfigs when ADDING percent uncertainties during multiplication/division of absolute uncertainties?
Definition
if added percent uncertainties are:
- greater than or equal to 2%, 1 sigfig
- less than 2%, no more than 2 sigfigs
Term
percent error
Definition
[(|actual - theoretical|) ÷ theoretical] x 100
Term
if % uncertainty > % error
Definition
- random errors
- instrument's fault
- more trials will help improve data
Term
if % uncertainty < % error
Definition
- systematic errors
- your fault
Term
Law of Conservation of Mass
Definition
- mass is neither created nor destroyed
- experiments showed combustion involved oxygen, not phlogiston
- Priestly, Lavoiser
Term
Law of Definite Proportion
Definition
- a given compound always contains exactly the same proportion of elements by mass
- constant composition of compounds
- Proust
Term
Law of Multiple Proportions
Definition
- molecular formula can be reduced to emperical formula
Term
Greeks questioned whether matter was:
Definition
1. continuous/infinitely divisible
2. composed of small, indivisible parts (Democritus of Abdera, Leucippos = coined the term atom)
Term
Greg Bauer/Paracelsus
Definition
laid foundations of chemistry
Term
Boyle
Definition
first chemist to perform truly quantitative experiments
Term
Dalton's Atomic Theory
Definition
1. each element is made up of tiny particles called atoms
2. the atoms of a given element are identical; the atoms of different elements are different in fundamental ways
3. chemical compounds formed when different elements combine
4. atoms themselves arent changed in chemical reaction, but reorganized
Term
isotope
Definition
same number of protons, different number of neutrons
Term
if all atoms are composed of these same components, why do different atoms have different chemical properties?
Definition
number and arrangement of electrons, therefore 3 of electrons possessed by given atom greatly affects its ability to interact with other atoms
Term
properties of atom: mass, # of protons, # of neutrons, # of electrons,
Definition
protons + neutrons, atomic #, mass - protons unless its an isotope, # of protons unless it has a charge
Term
chemical vs covalent vs ionic BONDS
Definition
- forces that hold atoms together, in general
- share electrons... form molecules
- transfer electrons... opposites attract
Term
radio isotope
Definition
isotope that contains an unstable nucleus
Term
element will decay if...
Definition
number of neutrons are too high or too low
Term
all atoms over __ protons are radioactive
Definition
83
Term
alpha particles
Definition
- positively charged
- ionizing radiation: strips electrons off things they pass through
- can't pass through paper or large clothing
*4,2,He on right side
Term
beta particles
Definition
- negatively charged
- neutron decays to a proton and electron (N --> P+ + e-
- smaller than alpha, therefore better at ionizing than alpha
- cant pass through 3 mm aluminum foil
*0,-1,e on right side
Term
gamma rays
Definition
- no charge
- not made of matter, PURE ENERGY = LOTS OF ENERGY, form of electromagnetic energy
- usually emitted after transmutation (nucleus changed)
- can't pass through 60 cm Al or 7 cm Pb
*0,0,Y on right side
Term
electron capture
Definition
- no charge
- proton is turned into neutron (P+ e- --> N)
- one of the inner-orbital electrons is captured by the nucleus
- *0,-1,e on left side
Term
positron emission (B+)
Definition
- positive charge
- instead of 0,-1,e it is 0,+1,e
- antimatter, destroyed when they encounter an electron
- electron + positron = 2 gamma rays
*0,+1,e on right side
Term
transmutations
Definition
collision caused a change in nucleus, the problems you solve the math to figure out blank elements and yadayada
- occurs in nuclear decay, fusion, and fission
Term
fission
Definition
splitting a nucleus into 2 or more elements, some mass lost, breaks law of conservation of matter, chain reaction, e=mc^2
Term
fusion
Definition
when 2 nuclei combine, lots of energy can be released, occurs in stars
Term
Geiger Counter
Definition
used to detect radioactive activity by measuring current that radiation produces in argon gas
Term
Ammonium, Carbonate, Chlorate, Chromate, Hydrogen Carbonate (bi), Hydroxide, Nitrate, Permanganate, Phosphate, Sulfate
Definition
NH4+, CO32-, ClO3-, CrO42-, HCO3-, OH-, NO3-, MnO4-, PO43-, SO42-
Term
Relative Atomic Mass (Ar)
Definition
mass of a single atom relative to C-12....isotope

isotope mass / mass of carbon (which is 12) = Ar
Term
Relative Molecular Mass (Mr)
Definition
sume of the Ar in a molecule
Term
percent composition
Definition
% mass of element = (mass of element/mass of compound) x 100
Term
molecular vs empirical
Definition
real amount and reduced
Term
limiting reactant
Definition
runs out first, SMALLER
Term
percent yield
Definition
(actual yield/theoretical yield) x 100
Term
percent to mass mass to mole divide by small multiply till whole.... method used when?
Definition
determining molecular/emperical formulas
Term
grams to moles to moles to grams......method used when?
Definition
stoichiometric caculations of limiting/excess reactants and products
Term
mass spectrometer
Definition
instrument used to determine the masses of atoms and their isotopic composition by the deflection of ions in a magnetic field

vaporization, ionization, acceleration, deflection, detection
VIADD!
Term
to find excess reactant
Definition
1. start with limiting ~ COMPARED TO ~ excess
Term
theoretical yield
Definition
maximum amount of a product formed when limiting reactant is completely used up
Term
to determine theoretical yield of a product
Definition
start with limiting reactant ~ COMPARED TO ~ product calculating theoretical yield for
Term
polar molecule
Definition
unequal charge distribution
Term
hydration
Definition
+ ends of water molecules attract to anions of ionic solid, and - ends of water molecules attract to cations of ionic solid
Term
when ionic substances (salts) dissolve in water, they break up into _______
Definition
INDIVIDUAL cations and anions
Term
when an ionic solid dissolves in water, ions become:
Definition
1. hydrated
2. dispersed
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