chem final Flashcards
to convert from one resonance structure to another, _
only electrons can be moved
elements _ exhibit similar physical and chemical properties
in the same group on the periodic table
group periodic table
vertical and down (same physical and chemical properties)
periods periodic table
across and horizontal and left to right
the gold foil experiment performed in Rutherford’s lab _
led to the discovery of the atomic nucleus
valence electron
the number of electrons on the outermost shell of an atom
how do u find valence electrons?
the number at the top row
alkali metals
group 1 metals
1 valence electron
highly reactive
soft (like butter)
low melting points
shiny
alkaline earth metals
group 2 metals
2 valence electrons
very reactive but less than alkali metals
harder than alkali metals
higher melting point than alkali metals
metal luster shiny
halogens
group 17
7 valence electrons
highly reactive
very colorful
transition metals
group 3-12
vary in everything
valence electrons based on orbitals
noble gasses
group 18
complete valence shell
highly stable
very unreactive
colorless, odorless, tasteless
low boiling and melting point
nonflammable
metalloids
on the line thing
between metals and non metals
metallic luster but brittle
moderate electrical conductivity
low thermal conductivity
nonmetals
right of metalloid line
metals
left of metalloid line
metalloid line
dividing line between metals and nonmetals
electron configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f14 6s2 6p6 6d10 7s2 7p6
ionic
metal + non metal
covalent
nonmetal + nonmetal
anion
negative charge (right)
cation
positive charge (left)
how do u find number of electrons
atomic number (bottom left)
how do u find mass number
protons + neutrons (top left)
how do u find number of protons
atomic number (bottom left)
how do u find number of neutrons
mass number - atomic number
top left - bottom left
which is NOT one of the postulates of Dalton’s atomic theory
atoms are composed of protons, neutrons, and electrons
which ARE some of the postulates of Dalton’s atomic theory
-each element is composed of extremely small particles called atoms
-atoms of an element are not changed into different types of atoms by chemical reactions: atoms are neither created nor destroyed in chemical reactions
-compounds are formed when atoms of more than one element combine; a given compound always has the same relative number and kind of atoms
-all atoms of a given element are identical; the atoms of different elements are different and have different properties
each s-subshell can accommodate a maximum of _ electrons
2
if a mixture is uniform throughout and can be separated into other substances by physical means, it is _
a homogeneous mixture
homogeneous
same thru the whole mixture
heterogeneous
different thru the whole mixture
what type of change: tarnishing of silver
chemical
what type of change: dissolving sugar in water
physical
what type of change: crushing of stone
physical
what type of change: melting of lead
physical
what type of change: dropping a penny in a glass of water
physical
element
substance made up of one type of atom
compound
a substance that is made up of more than one type of atom bonded together
mixture
a combination of two or more elements or compounds which have not reacted to bond together
what type of change: chopping a log into sawdust
physical
what type of change: charging a cell phone
chemical
what type of change: burning a plastic water bottle
chemical
what type of change: the tarnishing of a copper penny
chemical
what type of change: the production of hydrogen gas from water
chemical
cathode rays are deflected away from a negatively charged plate, leading to the discovery of _
negatively charged particles
all atoms of a given element have the same _
number of protons
all atoms of a given element can have different _
density, mass, number of neutrons, and number of electrons
octet rule
atoms try to make their outer shell full
element-mass number
element
(top left - mass)
(bottom left - atomic number/number of protons)
(top right - charge)
sig fig rules
-All non-zero numbers ARE significant
-Zeros between two non-zero digits ARE significant
-Leading zeros are NOT significant
-Trailing zeros to the right of the decimal ARE significant
-Trailing zeros in a whole number with the decimal shown ARE significant
moles to grams
multiply by molar mass
grams to moles
divide by molar mass
going TO mole island
divide
leaving mole island
multiply
atom/molecule to mole
divide by 6.022 × 10²³
mole to atom/molecule
multiply by 6.022 × 10²³
liter/volume to mole
divide by 22.4L
mole to liter/volume
multiply by 22.4L
precision
how close a measured number is to other measured numbers
accuracy
how close a measure number is to the ACTUAL value
an empirical formula always indicates _
the simplest whole number ratio of different atoms in a compound
molecular formula
how many atoms of each element are in a compound
when a hydrocarbon burns in air, a compound produced is _
carbon dioxide and water
synthesis (types of reactions)
2 to 1
H + Cl –> HCl
decomposition (types of reactions)
1 to 2
HCl –> H + Cl
single replacement (types of reactions)
1 is changed around
AlCl + Br –> AlBr + Cl
double replacement (types of reactions)
2 are changed around
NaCl + KBr –> KCl + NaBr
combustion (types of reactions)
ANYTHING reacts with oxygen
King Henry Died By Drinking Chocolate Milk (0.001 –> 1000)
small to big
(remember to cancel out the units)
divide
243 / 100 cm = 2.43m
King Henry Died By Drinking Chocolate Milk (0.001 –> 1000)
big to small
(remember to cancel out the units)
multiply
243m x 100 cm = 24300cm
m/s –> km/hr
convert m to km
convert s to hr
how do u find the empirical formula?
- divide each percent by the molar mass
- divide the ending molar masses by the smallest molar mass
- the number you get goes in the formula
EX: 3C, 6H, and 2O –> C3H6O2
how do u find the molecular formula?
- take empirical formula
- multiply by molar mass
- add the molar masses together
- use the given mass and divide it by the molar masses total
- multiply the empirical formula by the answer in step 4
EX: (given-290g/mol)/(calculated thru steps 1-3(58.09g.mol)) = 5
5 x (C3H6O2) = C15 H30 O10
PV =
nRT
pressure x volume =
moles of gas x ideal gas constant (0.08206) x temperature in K (C + 273)
crystalline solids _
have highly ordered structures
sublimation
solid to gas
polar
lewis dot is not even, and its strong ish, dipole-dipole
if a lewis dot is even, and there are dots on the outside but not the inside, it is _
not polar
if a lewis dot is even, and there are dots in the middle but not the outside, it is _
polar
non polar
lewis dot is even, and its weak, london dispersion
strong to weak intermolecular forces
ionic, hydrogen, dipole-dipole, london dispersion
weak to strong intermolecular forces
london dispersion, dipole-dipole, hydrogen, ionic
ionic intermolecular force
metal and non metal, or + <–> -
hydrogen intermolecular force
Hydrogen + F, N, or O
dipole-dipole intermolecular force
polar = non even
<– <–
–> –>
different charge everywhere
london dispersion intermolecular force
non polar = even
–> <–
<– –>
same charge everywhere
how does atomic radius increase
left and down
how does electronegativity increase
up and right
how does ionizing energy increase
up and right
bent/angular
2 surrounding atoms
1 or 2 lone pairs
<120* if 1 lone pair
<109.5* if 2 lone pairs
trigonal pyramidal
3 surrounding atoms
1 lone pair
<109.5*
trigonal planar
3 surrounding atoms
0 lone pairs
120*
tetrahedral
4 surrounding atoms
0 lone pairs
109.5 degrees
linear
2 atoms
180*
2 surrounding atoms w/ 0 lone pairs
non polar covalent number
<0.3
polar covalent number
0.3 < x < 1.7
ionic number
1.7<
deposition
gas to solid
changing phases formula (straight line on graph)
q = n(ΔH)
q=heat
n=moles of substance
ΔH=mole enthalpy (energy per moles) KJ/mol
ΔH fusion number
6.02
fusion
melting / solid to liquid
ΔH freezing number
-6.02
ΔH vaporization number
40.6
ΔH condensation number
-40.6
changing temp formula (diagonal line on graph)
q = mCΔT
q=heat
m=mass in grams
C=heat capacity
ΔT=change in temp (final-initial)
water specific heat capacity number
4.184 J/gxC
one significant difference between gases and liquids is that _
a gas expands to fill its container
1 atm = _ torr
760
1 atm = _ mmHg
760
1 atm = _ psi
14.7
1 atm = _ kPa
101.325
pressure conversions formula
given x (transforming value / given value) = given transformed value
in liquids, the attractive molecular forces are _
strong enough to hold molecules relatively close together but not strong enough to keep molecules from moving past each other
the weakest interparticle attractions occur between particles of a _ and the strongest interparticle attractions exist between particles of a _
gas, solid
Avogadro’s law
volume and number of moles in a gas are directly related
inversly related
one increase, other decrease
directly related
one increase, other increase
boyle’s law
pressure and volume are inversely related
charles’ law
volume and temp are directly related
Gay-Lussac’s Law
pressure and temp are directly related
gas laws formula
PV/T = PV/T
gas laws formula: if it’s multiplied, it is _ related
inversely
gas laws formula: if it’s divided, it is _ related
directly
STP (standard temp & pressure)
273 K
1 atm
how do u do gas stoichiometry at STP?
g –> mol –> other element mole/current element mole –> volume (22.4L/1mol)
how do u do gas stoichiometry not at STP? (ideal gas law formula)
- convert moles
- V = nRT / P
V = volume
n = moles
R = 0.08206
T = temp in K
P = pressure
mole fraction / partial pressure formula
Xi = ni / ntotal
Xi = mole fraction
ni = # of mole component
ntotal = total # of moles
partial pressure formula
pressure A = ((volume B x pressure B) - (volume C x pressure C)) / volume A
beta particle
0 / -1 e
positron
0 / 1 e
emission
1 / 0 B
alpha
4 / 2 e
triple point
solid, liquid, and gas at the same time
supercritical fluid
liquid and gas at same time
molecules with stronger intermolecular forces have higher _ _
melting points
in general, as activation energy increases, reaction rate_
goes down regardless of whether the reaction is exothermic or endothermic
exothermic
releases heat
endothermic
absorbs heat
the reaction rate depends on _
all of the above
at equilibrium, _
the rates of the forward and reverse reactions are equal
first order reaction
k[element]^1
second order reaction
k[element]^2
the magnitudes of Kf and Kb depend on the identity of the _
solvent
the _ is the material that usually decides the solution’s physical state (solid, liquid or gas)
solvent
A solution of salt and water, for example, has water as the solvent and salt as the solute.
the _ is the product that the solvent dissolves
solute
A solution of salt and water, for example, has water as the solvent and salt as the solute.
how do u write the equilibrium constant
products / reactants
specific heat capacity formula
q=mcAT
q=energy
m=mass in grams
c=specific heat capacity
AT=temp change
the phrase “like dissolves like” refers to the fact that _
polar solvents dissolve polar solutes, and nonpolar solvents dissolve nonpolar solutes
∆S is _
entropy
∆H is _
enthalpy
in general, as temp goes down, reaction rate _
goes down regardless of whether the reaction is exothermic or endothermic
in general, as temp goes up, reaction rate _
goes up regardless of whether the reaction is exothermic or endothermic
If the volume of the container is increased (at constant T), the system will shift in the direction that _ the number of moles of gas in the container
increases
If the volume of the container is decreased (at constant T), the system will shift in the direction that _ the number of moles of gas in the container
decreases
catalyst
reactant –> product
intermediates
product –> reactant
how do u write rate law?
rate=k[A]^m[B]^n
k=rate constant
A and B=reactants
m and n=orders (how much they affect the reaction)
in general, as temperature goes up, reaction rate _
goes up regardless whether the reaction is exothermic or endothermic
in general, as temperature goes down, reaction rate _
goes down regardless whether the reaction is exothermic or endothermic
solution
everything is even
homogenous
solute + solvent =
solution
what affects dissolving rate?
surface area - substance pulls apart more
stirring - clears dissolved particles out of way and allows water to pull apart rest of substance
temp - high temp means molecules move faster and can pull apart faster
concentration
how strong a solution is, and how much has been dissolved
dilute solution
not much has been dissolved
concentrated solution
a lot has been dissolved
molarity definition
amount of moles that have been dissolved in a specific volume of a solution
molarity formula
moles of solute / liters of solution
mol / L
dilution formula
M1V1 = M2V2
M = molarity
V = volume
a solid is formed
known as precipiate
When two solutions are mixed, there are a few signs that a reaction has actually occurred:
a solid, gas, or liquid is formed
soluble
dissolves in water
aka dissociation
insoluble
doesn’t dissolve in water
stays as a solid
Colligative properties
properties that depend on the concentration of the solute dissolved in solvent and that will change the normal properties of the solvent
Freezing Point Depression
By adding a solute to water, the water will now have a lower freezing point
Boiling Point Elevation
By adding a solute to water, the water will now have a higher boiling point
Electrolytes
substance that dissolve into their separate ions and allow water to conduct electricity (ionic)
Non-electrolytes
substances that dissolve, but do not break into different ions (covalent) (i=1 always)
freezing point depression formula
∆t = Kf x m x i
∆t = change in freezing point
Kf = -1.86 (freezing point constant for water)
i = van hoff’s factor (number of particles)
m = molality
boiling point elevation formula
∆t = Kb x m x i
∆t = change in temp
Kb = boiling point constant for water (0.51)
i = number of particles
reversible reactions
can go in both directions
if Keq < 1 and Q > K, _ is favored
reverse reaction
more reactants than products
if Keq > 1 and Q < K, _ is favored
forward reaction
more products than reactants
if Q = K, the reaction _
is at equilibrium
Le Chatelier’s Principle states
a system will always try to be at equilibrium
what are the 3 ways to stress a system?
change pressure, concentration, or temp
changing the pressure only affects the system if there is a _
gas
if the pressure increase, the volume will _
decrease
With less volume, the system will move to the side of the reaction that has fewer moles of gas
if the pressure decrease, the volume will _
increase
With a larger volume, the system will move to the side that has more moles of gas
if we increase concentration, there is _ of a substance. the reaction moves in the direction that uses up the _
extra
if we decrease concentration, there is no longer _ of that substance. the reaction moves in the direction to replace the ) substance
enough, missing
temperature: exothermic
energy is a _
product
temperature: endothermic
energy is a _
reactant
decrease temp changes how much _ there is. we do the same thing as with _
energy
concentration
aq solutions are when ions get _
separated
In order for a reaction to occur, the molecules must _ in the correct orientation and with enough energy to break the bonds. Once the bonds are broken, new bonds can be formed and a new molecule is made
The energy required to do this is called _ _
collide
activation energy
what are the several factors that determine how quickly a reaction will take place?
nature of reactants
surface area
temp
concentration
rate laws are used to determine how _ a reaction can take place
quickly
Energy flows in or out of a reaction because
molecules require energy to keep the atoms bonded together
negative ΔH means energy is lost by the system, or is _
exothermic
positive ΔH means energy is gained by the system, or is _
endothermic
activation energy (Ea)
Minimum energy required for particles to collide and react
catalyst
speeds up reaction
Many reactions do not happen in one single step, but instead require multiple reactions to get the desired results is who’s law?
hess’s law
rate determining step
slowest step in reaction
slowest step in diagram has highest
activation energy
the entropy of a pure crystalline substance at absolute zero is _
0
entrophy meaning
the measure of randomness in a system
standard entropies increase with _
molar mass and number of atoms
For a reaction to be spontaneous, it means that the reaction can happen without any _
outside influence
In order for a reaction to be spontaneous, ∆Suniverse must be
positive
∆G means _
Gibb’s free energy
∆G formula
∆G = ∆H - T∆S
free energy = enthalpy - temp in K x entropy
whats an acid?
a substance that has an H+ ion
whats a base?
produces OH- and accepts H+
what are Conjugate pairs?
shows us how a reactant changes to become a product (follow the anion)
conjugate base
the substance created after H+ has been donated (removed)
anion of acid
paired with acid
conjugate acid
the substance created after H+ has been accepted (added)
made from base
paired with base
_ has a pH of 7
pure water
< 7pH
acidic
more hydrogen
> 7pH
basic
more hydroxide
A strong acid produces a _ conjugate base
We say the _ reaction is favored
weak
forward
A weak acid produces a _ conjugate base
We say the _ reaction is favored
strong
reverse
Titration
is a controlled addition and measurement of a solution with a known concentration to react with a solution of unknown concentration
Standard solution
a solution in which we know the concentration
Equivalence point
point at which there are equal amounts of moles of each solution
Endpoint
the point in the titration where the indicator has changed color
Indicator
a substance used to show when the is a change in pH (going from basic to acidic or from acidic to basic)
Most common is phenolphthalein
Turns pink when solution becomes basic
Electrochemistry
the study of the relationships between electricity and chemical reactions
chemical cell
a battery, where two different metals are used.
One metal will oxidized and the other metal will be reduced.
A battery “dies” when this process can no longer be continued.
redox reaction
one substance undergoes reduction and the second substance is oxidized, both of which happen because of a change in number of electrons
If the oxidation number decreases for an element, that element is _
reduced
If the oxidation number increases for an element, that element is _
oxidized
oxidation numbers: elements, not ion form
0
oxidation numbers: monatomic ion (ion of one type of atom
charge
oxidation numbers: F (when in a compound)
-1
oxidation numbers: O
–2 (unless peroxide = –1) (when in a compound)
you know it’s peroxide based on the cation it is bonded with
oxidation numbers: H
+1 (unless a metal hydride = –1) (when in a compound)
The sum of the oxidation numbers equals the overall charge:
(0 in a compound)
a species is _ when it loses electrons
oxidized
a species is _ when it gains electrons
reduced
how do u balance redox equations
- make 2 half reactions (oxidation and reduction)
- balance the atoms other than O and H first
- balance O using H2O and H using H+
- add electrons to balance charges
- Multiply by common factor
to make electrons in half-
reactions equal. - Add the half-reactions.
- Simplify by dividing by common factor if necessary.
- Double-check atoms and charges balance!
voltaic cell other name
galvanic cell
voltaic cell oxidation occurs at the _
anode
voltaic cell reduction occurs at the _
cathode
voltaic cell meaning
a device that generates electrical energy thru a chemical reaction
_ are formed in the anode compartment as the metal dissolves
cations
As the electrons reach the cathode, cations in solution are attracted to
the now negative _
cathode
The potential difference between the anode and cathode in a cell is called the _.
It is also called the cell potential and is designated Ecell.
For a spontaneous cell, the cell potential must be positive
electromotive force
EMF
measured in volts (V)
The more positive the value, the more likely the reaction is to occur as written
So to decide which substance is more likely to reduce, look for the one with the larger _
E°
The cell potential at standard conditions can be found through this equation:
Ecell = Ered (cathode) – Ered (anode)
