unit 1 Flashcards
includes all unit 1 power points and study guide information. also all practice problems (not math)
use substance and element in a sentence that describes relation
an element is a pure substance. the other pure substance is a compound.
use substnace and mixture in a sentence that describes relation
a mixture is composed of 1 or more pure substances combined in variable proportions
is it easier to prove an unknown substance an element or compound
compound
mixtures are classified by their
properties
classification of seawater
mixture
4 properties of metals
malleable
ductile
lustrous
good conductors
4 properties of nonmetals
poor conductors
brittle as solids
dull
gases at room temp
1 chemical property of metals
oxides react with water to form hydroxides
1 chemical property of nonmetals
oxides react with water to form acids
is CO2 organic or inorganic
inorganic
is H3PO4 molecular or ionic
molecular
rf=
distance spot moved/distance solvent moved
difference in ideas of atom development between democritus and dalton
democritus: no experimental evidence to support idea
dalton: had experimental evidence
what evidence led thompson to determine that cathode ray was beam of negative particles
attracted to positive CRT
repelled by negative cathode
why did rutherford conclude that nucleus has a positive charge
alpha particles have a positive charge. a few deflected off gold foil, Rutherford concluded deflected thing had a positive charge
problems with rutherfordś model
e- should lose energy and be pulled into nucleus
atom should collapse
electrons are acellerating charges
why was planckś theory not accepted at first
behavior of waves and particles are seen differently and supported by experiments and math
E=
hv
h(c/lamda)
h=planck’s number
v=frequency
c=speed of light
lamda=wavelength
h (planck’s number)
6.626 x 10^-34 J x s^-1
6 types of radiation in order of lowest to highest eneergy
infared
red
blue-green
blue
violet
uv
contrast Bohr and debroglie electrons
bohr: fixed energy levels, didnt know why they existed
debroglie: theoretical foundation for fixed energy levels that involved looking at wave properties of particles
how did Heisenberg and Schrodinger see electron differently
Heisenberg: complex equations, particle w quantum behavior
Schrodinger: mathematics, wave phenomenon
contrast borh’s energy level and quantum mechanical model
bohr: e- follow fixed paths around nucleus
qmeo: quantized energy, impossible to find electrons, e- found in atomic orbital, shows probability of finding an electron
n shows
principal quantum number
size
energy levels
l shows
shape
number of different shapes (sublevels)
m
orientation in space
lobes of orbital disappear at nucleus. what does this mean?
0% chance of finding an e-
why does the 4s sublevel have lower energy than 3d
energies get closer together as n inclreases
repulsive forces means n has higher energy
3d has 5 orbitals while 4s has 1
allotropes
elements that exhibit different groupings of atoms
elements that border metalloids
ex. diamond, graphite, carbon, phosphorous
how do you know if a compound is organic?
contains carbon
almost all have a C-H bond
how do you know if a compound is ionic?
contains a metal and nonmetal
acids
contains hydrogen ion(s)
bases
contains/produces hydroxide ions
salts
ionic compounds without hydroxide
colloid
mixture that has very small particles distributed evenly in another substance
homogenous
homogeneous mixture properties
appears same throughout
particles smaller than 1 um
solution-substances do not aggregate to from particles (solute-solvent)
heterogeneous
doesn’t appear same throughout
particles larger than 1 um
one or more compounds visible
suspension
dispersed phase and continuous medium
heterogenous
elements are classified based on their
properties
compounds are classified based on their
composition
potassium fluoride classification
compound
carbon classification
element
classification of something that contains more than one substance
mixture
density separation
used to separate solids with different densities
one liquid is denser than the other in the mixture
less dense liquids will float to top
must be insoluble in each other
filtrate
liquid that passes through the filter paper
mobile phase
liquid/gas carries mixture in chromatography
stationary phase
used to place the mixture on
mobile phase travels up this
components travel up this at different rates based on their attractions/affinities for this
substances with a strong attraction for this will not travel far (vice-versa)
paper chromatography
stationary phase: paper
mobile phase: solvent
filtration
mixture poured through filter to separate
decanting
gradually pour off a liquid to separate them
centrifugation
spinning solutions around an axis at high speed to separate them
column chromatography
stationary phase: tube packed with specially treated resin beads
mixture poured into one end of tube
mixture travels through beads
components separate
each component collected at the other end of the tube at different times
Rf= time component exited tube/time required solvent to exit
distillation
uses different vapor pressures/boiling points of mixture to separate
how to separate solution of aq copper sulfate, wood shavings, and iron filings?
use a magnet to attract iron filings
use filtration to separate wood and copper sulfate
distill copper sulfate from water
what’s the difference between decomposing compounds and separating mixtures?
decomposing is chemical
separating mixtures is physical
explain chromatography
mobile phase carries each component of a mixture at a different rate through the stationary phase
each component travels at its own rate though the stationary phase based on its attraction to each phase
problems of distillation and how to fix it
liquids evaporate before they reach their boiling point
fix: distill the liquid several times to successfully remove the liquid with the higher boiling point
does chromatography or distillation require more energy?
distillation requires heat energy
chromatography relies on phase attractions
democritus
-proposed atoms
-no experimental evidence
law of conservation of mass
matter cant be created/destroyed
law of definite proportions
all samples in a given compound have the same proportions of their constituent elements
law of multiple proportions
Dalton reasoned that when 2 elements form 2 compounds, the products can be expressed as a ratio of whole numbers
atomic mass units are based on
the size of that atom compared to a hydrogen atom
Dalton’s theory
all matter is composed of atoms which can’t be created or destroyed
atoms of the same element are identical
atoms of different elements combine in simple, whole number ratios to form compounds
atoms are separated, rearranged, and recombined in chemical reactions to form new compounds
consistent with Dalton’s theory?
sulfur and oxygen have the same mass
no