New Chem/Phys Flashcards
proton
positive charge and a mass of 1 amu
neutron
no charge and mass of 1 amu
electron
negative charge and mass of 0
nuculeus
contains protons and neutrons, electrons flot around nucleus
atomic number
number of protons in a given element
mass number
sum of elements protons and neutrons
atomic mass
equal to the mass number, sum of protons and neutrons
isotopes
atoms of a given element (same atomic number) but have different mass numbers. differ in number of neiutrons
atomic weight
weighted average of the naturally occurring issues
periodic table lists these
rutherford
first said that the atom had a dense, + charged nucleus made up only a small fraction of the volume of the atom
Bohr model of an atom
dense positive charge nucleus surrounded by electrons that revolve around a nucuekus in orbit with distinct energy levels
the energy difference between levels is called a
quantum
quanitization
not an infinite range of energy levels available to an electron, electrons can exist only at certain E levels. E of an electron increases as it is farther from the nuc
atomic absorption spectrum
electron to jump from a lower E level to a higher E level, must absorb the amount of energy equal to the energy difference between the 2 levels
when electrons return from the excited state to ground state, they
emit the amount of energy that is exactly equal to the energy difference between the 2 levels. atomic emission spectrum
quantum mechanical model
electrons do not travel in defined orbits, but localized in orbitals
orbitals
a region of space around the nucleus defined by the probability of finding an electron in that region
Heisenberg uncertainty pricniple
impossible to know an electrons position and its momentum exactly at the same time
quantum numbers
n, l, m1, ms
principal quantum number
n. describes the energy of a shell.
azimuthal quantum number
l. describes the sub shells within a given principal energy level (s, p, d f, )
magnetic quantum number
m1 specifics the particular orbital within a subshell where an electron is likely to be found at a given moment in time
the spin quantum number
ms. indicates th spin ordinations with +1/2 and -1/2 of an electron in an orbital
electron confiuhration
ex. magnesium. 12 electrons
1s2, 2s2, 2p6, 3s2…
3p6, 4s2, 3d10, 4p6, 5s2, 4d10, 5p6
f has 14
electrons fill the principal energy level and subshells by this role
n +1 rule
HUnds rule
sub shells with many orbitals (p, d , f ) fill electrons so that every orbital in a subshell gets one electron before any of them get a second
paramagnetic
have unpaired electrons that align with magnetic fields, attracting material to a magnet
dimagnetic
materials have all paired electrons which cannot easily be realigned, repelled by magentis
valence electrons
electrons in outermost shell available for interaction (bonding) with other atoms
the difference in energy between 2 shells decreases as teh distance from the nucleus inceases
energy difference between 3 adn 4 s less than energy difference between 1 and 2
maximum number of electrons in a shell
2n^2
m1 can only be between -L and +L
yes
subshell s, p, d, f
L:
0,1,2,3
electrons:
2,6,10,14
unpaired electrons in the ground state example
helium . repelled by magments
E=hc/wavelength
energy
h= 6.6 x 10 ^-34
c=3.00 x 10^8-speed o light
wavelength of light
if you do something with “1 mole”
multiple by avogadros number
6.02 x 10^23
spins in the same direction
parallel
periodic table organizes elements according to their
atomic number
rows are
called periods and based on teh same pricipal energy level (n)
columns are called
groups, have the same valence shell configuration
metals
shiny, lustrous, conduct electricity, malleable and ductile. metals on L side and middle
nonmetals
dull, poor conductors, brittle, R side
metalloids
metals and nonmetals and with boron stepping pattern
Zeff
effective nuclear charge- net positive charge experienced by electrons in their valence shell
increases from L to R,
valence electrons become increasingly separated from the nucleus as the principal energy level (n) increases from top to bottom in a group
atomic radius
decreases from L to R acrosss a period and increases from top to bottom in a group
ionic radius
size of charged species. increases as you move from top to bottom on the periodic table. Ionic radius decreases as you move across the periodic table, from left to right. cations smaller than neutral, anions greater than neutral
ionization energy
amount f energy needed t o remove an electron from the valence shellof a gas - increases from L to R and decreases from top to bottom
electroneg
F!!! measure of attractive force of the nucleus for electron within a bond. increases from L to R across a period and decreases from top to bottom
alkali metals
oxidation state of +1 and prefer to lose an electron to achieve Nobel gas state- very rective
all the way on the outside of L
alkaline earth metals
oxidation state of +2 and can lose 2 electrons to achieve noble gas configurations. reactive
form divalent cations (ions with +2 charge)
halogens
oxidation state of -1 and can gain electrons too have noble gas configurations.
highest electroneg
noble gases
fully filled valence shell and prefer to not give up
high ionization E (for HE, NE and AR) with no electroneg and electron affinities
metalloid
between metals and and transition metals
what forms with water well
transition metals. because have many oxidation states
within the same period, an additional valence electron is
added with each step to teh R of the table
ionic bonds
unequal sharing of electrons. formed via the transfer of one or more electrons from an element with low ionization E to an element with high electron affinity.
occur between elements with large differences in electroneg (metals and nonmetals)
elements with an incomplete octet that are stable with fewer than 8 electrons
H, He, Li, Be, B
ionic ions dissociate in
polar solvents and water
ionic ions have high
melting point
covalent bond
formed via the sharing of electrons between two elements of similar electroneg.
bond order
refers to whether a covalent bond is a single bond, double or triple. as bond order increases, bond strength increases, bond energy increases and bond length decreses
non polar bonds covalent bonds
atoms that have the same electroneg
polar bonds covalent
significant difference in electro but not enough to transfer electrons to form an ionic bond. the more electroneg atom takes on the partial negative charge
coordinate covalent bond
single atom provides both bonding electrons while the other atom does not contribute any.
Lewis acid base chem
formal charges
when an atom is surrounded by more or fewer valence electrons than it has in neutral state (assuming equal sharing of electrons in a bond)
V-Nonbonding-1/2bonding
valence electrons
lewis acid
any compound that will accept a lone pair of electrons
lewis base
any compound that will donate a pair of electrons to form a covalent bonds
resonance
any molecule with pi system or duke bonds
represent all possible confirmations of electrons
small or no formal charge > formal charge
less separation between opposite charges > large seperation
negative formal charge is on electroneg atom > negative formal charge on less electroneg atom
all elements beyond third period can take more
than 8 electrons in their valence shell and form more than 4 bonds
VSEPR theory
molecular geometry
determined by repulsions between bonding and nonbonding electrons
linear (BeCL2), trigonal planar (BH3), tetrahedral (CH4),trigonal byprimada (PCL5), octahedral (SF6)
180,120,109.5, 90/120/180, 90/180
electronic geometru
describes the spatial arrangement of all pairs of electrons around the central atom, including bonding and lone pairs
H20, CH4 and NH3 all have 4 pairs of electrons around the central atom- tetrahedral
molecular geometry
describe teh spatial arrangement of only the bonding pairs
H20, CH4 and NH3- bent, tetrahedral; and trigonal pyramidal because different coordination number
coordination number- the number of atoms that surround and are bonded to a central atom
CCL4- non polar or polar?
non polar. although CL is electroneg and pulls, cancels each other out in all 4 directions
when orbitals overlap head to head
sigma bond
free rotation of axes because electron density is single linear
two parallel electron cloud
pi bonds. no free rotation because parallel and cannot twist
intermolecular forces
electrostatic interactions between molecules
weaker than covalent bonds (which are weaker than ionic)
LDF
weakest, present in all
as the size of the atom increases, so does LDF
dipole dipole
occur between oppositely charged ends of polar molecules.
not in gas phase due to distance in particles
hydrogen bonds
specialized idols
H is bonded to F, O N- electroneg atoms
large intermolecular forces
higher BP
Kr= octet
ionic bonds are strongest
bond lengths decrease with larger differences in
electronegative
ammonium
NH4+
ammniia
NH3
ion dipole interaction
the result of an electrostatic interaction between a charged ion and a molecule that has a dipole.the interaction between a Na+ ion and water (H2O) where the sodium ion and oxygen atom are attracted to each other, while the sodium and hydrogen are repelled by each other.
mole
quantity of any substance (atoms, molecules, etc)equal to the number of particles that are found in 12 g of C
defined as avoados number - 6.022 x 10^23
molecular weight vs. molar mass
amu/molecule and g/mol
moles =
mass of sample (g)/molar mass (g/mol)
gram equivalent weight
molar mass/n
n= number of particles of interest produced or consumed per molecule of the compound
ex. one would need 31 g of H2Co3 (molar mass 62 g/mol) ti produce an equivalent of hydrogen ions because each mol of H2Co3 can donate 2 hydrogens (n=2)
equivalents
mass compound (g)/gram equivalent weight (g)
normality
mesure of concentration
equivlants/L
hydrogen ion concentration
1N solution = hydrogen ions equal to 1 mole per liter. 2N acid solution = 2 moles of hydrogen ions per liter
in a 1N HCL solution the molarity of HCL is
1 M because HCL is monoprotic
in a 1 N H2CO3 solution the molarity is
0.5 M because diuretic acid
normality
molarity x n
n= numbest of protons, ions, electrons consumed by the solute , H+ ions or OH IONS
molarity=
mol/L
empirical formua
simplest whole number ratio of the elements in the compound
CH- benzene
molecular formula
exact number of atoms of each element in the compound and is a multiple of the empirical formula
C6H6- benzene
percent composition
mass of element in formula/molar mass x 100
ex. what is the percent composition of Cr in K2Cr2O7
molar mass = 292 g/mol
Cr: 2 x 52
combination reaction
has two or more reactants forming 1 products
decomposition reaction
opposite of combination
single reactant breaks down into 2 or more products
combustion rection
hydrocarbon (fuel) and oxidant (oxygen) to form CO2 and water
Ch4 + 2 O2 –> CO2 + h20
single displacement
when an atom or ion in a compound is replaced by an atom or ion of another element
Cu + AgNO3 – Ag + CuNO3
double displacement
metathesis reactions
each swap
neutralization reactions
acid with base to produce a salt.
Hcl and NAOH will produce NaCL and H20
limiting reagent
limits the amount of product that can be formed in the reaction because it is used up first
theoretical yield
max amount of product that can be generated as predicted from the balanced equation, AAUMIGN ALL LIMITED REATANT IS consumed.
actual yield
the amount of product one actually does obtain during rection
percent yield
actual/theoretical x 100
cations
usually metas
anions
usually nonmetals
oxidation states
different charges
solutes that enable solutions to carry currents
electrolytes
-ous
lesser charge
-ic
greater charge
The solute concentration will affect the size of spots on a paper chromatogram, .
not the average migration rate
Rf=
= (distance traveled by aspatic acid)/(distance to the solvent front)
during a dehydration reaction
a carbocation forms, which leads to non stereospecific (trans and cis) results
What type of functional group is formed when aspartic acid reacts with another amino acid to form a peptide bond?
AMIDE GROUP
The functional group that represents a peptide bond is called an amide group.
An amine is one of the functional groups that reacts to form a peptide bond, not the peptide bond itself.
1,2-hydride shift
a carbocation rearrangement in which a hydrogen atom in a carbocation migrates to the carbon atom from an adjacent carbon (carbon 1).
In gas-liquid chromatography, the first peak to emerge will be from the least polar, most volatile compound.
hydrogen bonds= non volatile (like in alcohols)
dipole dipole (like with BR and CL)- less volatile
LDF= volatile (bonde to just a methyl group
1 cm=
.01 M
1 m
100 cm
40 cm=
0.4 M
100 M
1000 cm
The negative sign of the lens strength is indicative of a
diverging lens
enzymes affect chemical reactions by Stabilization of:
the transition state changes the activation energy of the reaction.
ionization is
ionization is the loss or gain of charge through H atoms.
ohms law
V=IR
index of refractio
=speed of light in vacuum/ the speed of light in the medium,
n= c/v
E (photon E)=
hf
h= planks constant = 6.626 * 10-34
f=frequnecy
speed of light =
frequency x wavelength
intensity of the radiation
is rested to number of photons emitted
THz=
1 x 10^12 Hz
standard atmospheric pressure is
760 mmHg or 1 atm
radioactive decay law
N(t) = N (1/2)t/T
1 mL
0.001 L
work and power equation
P = W/t
time is in secondos
The high number of capillaries in the body means that the total cross-sectional area of these vessels is larger than any other vessel type in the circulatory system.
This causes the velocity of the blood to decrease.
BP is higher in the
arteries than capillaries
Which of the following types of orbitals of the central atom are involved in bonding in octahedral compounds?
Octahedral compounds have six σ bonds and no stereochemically active lone pairs. According to valence bond theory, the central atom requires the hybridization of six atomic orbitals, d2sp3
when there are more than 4 bonds, the sp3 hybridized orbitals can’t accommodate the number of bonds, so it need to recruit the d orbital?
octahedral molecules have six atoms bonded to the central atom and no lone electron pairs,
The molar volume of an ideal gas at 25°C is 24.4
not 22.4
Retinal is composed of mainly carbon and hydrogen
making it largely hydrophobic.
gamma decay
emission of a proton
negative delta G means
positive delta S for sponteous reaction
Gibbs free E
determines whether or not a reaction will occur by itself without outside assistance
not necessarily mean quickly -no help with catalyst
colliosn theory of chemical kinetic
the rate of the reaction is proportional to the number of collisions per second between reacting molecules
activation E
the minimum energy of collision necessary for a reaction to take place
Arrhenius Equation
k- rate constant of reaction A= frequency factor Ea= activation E R- ideal gas connate T- temp
k= Ae^ (-Ea/RT)
rate of reaction
increases with temperature
more molecules present
transition state
has greater E than both the reactants and the products
energy required to reach here is the activation E. can either go to products or reactants
free energy change of the reaction
difference between the free E of products and of reactants
-= exergonic
+= endogeronic
exergonic
energy is given off
endergonic
energy is absorbed
reaction rates are measured in terms of
the rate disappearance of a reactant or appearance of a product
rate laws general form
k[A]^x[B]^y
x and y are determined EXPERIMENTALLY not coefficients
rate is measured in
molarity (M)/seconds (s)
zero order
formation of product C is independent of changes in concentration of any of the reactants
constant reaction rate equal to rate constant K
A and B raised to 0.
change by adding a catlyst or temperature
linear decreasing graph
first order reactions
rate is directly proportionate to only one reactant
A and B raised to 1
slightly curved line
second order reaction
propinate to the concentration of 2 reactants or square concentration of a singlee reactant
A and B raised both to 1 or A or B raised to 2
mixed order reactants
catalyst is invovled
reactions with rate orders that vary overt time
if they tell u that the rate is “third order”
the sum of the exponent in the rate law must be equal to 3. s
changing the concentration of the reactants will not change the rate in a
0 order reaction rate
solvents affect the rate of reaction
along with temperature, partial pressure of gas (how molecules collide) but products have nothing to do with reaction rate so changing that is fine
saturated solutions with a catalysts have a max turnover rate and cannot increase the rate constant or
the reaction rate any higher by adding more reactant
the overall order of a reaction is the
sum of the individual orders of the reaction
lowest activation eneegru means
fastest rate
the law of mass action
for a reversible reaction, if the system is at equilibrium at a constant temperature than
Kc=Keq= concentration of products raised to their coefficient/reactants raised to their coefficient
forward and reverse reaction rate constants
Kf and Kr
Keq= Kf/Kr
reaction quotient
at any point in time during the reaction, can measure concentrations of all the recctants and products using the same Keq formula
concentration of products raised to their coefficient/reactants raised to their coefficient
Q< Keq
forward reaction has not yet reached equilibrium
reactants are greater in concentration
forward rate increased to restore equilibrium
Q=Keq
reaction is in dynamic equilibrium
forward and reverse are equal
Q>Keq
forward reaction exceeded equkiriu
greater concentration of products
reverse rate is increased
if teh equkibirum for a reaction is written in one direction to be keq
reverse reaction. is 1/keq
Keq is
temperature dependent
Keq>1
products are present in greater concentration at equlibrium
Keq=1
products and reactants are both present at equilibrium at simiar level
Keq<1
reactants are present in greater concenrtation
Keq«1
amount of reactants converted to products is very small
Keq=
x^2/1-x
x on the denominator is negligible
when Keq is largely negative
Le Chateliers
when a chemical system experiences a stress, it will rect so as to store equilibrium
stress can beL changes in concentration, pressure, volume and temperature
increasing gate concentration of reactants or decreasing products will shift
to the right
increasing products
shift to left
increasing pressure on gas system (decreasing volume)
shift to fewer moles of gas side
known by coefficient
decreasing pressure (increase volume)
shift reaction to side with more moles of gas
known by coefficient
increase temp of endothermic reaction or decreasing temp of exothermic reaction
reaction shift to R
decreasing temp of endothermic or increasing temp of exothermic
shift to the left
kinetic products
higher in free E than thermodynamic products adn can form at lower temp. f
fast products because they can form more quickly under such conditions
free E is lower than thermodynamic products
thermodynamic products
lower in free E and more stable than kinetic
more sponetous tho
solids are NOT IN EQUILIBIRUM EXPRESSSIONS
ONLY GASES
Kc
concentration equilibrium
Kp
pressure equilibrium
exothermic reaction produces heat so decreasing the temperature
favors product formation, increase of forward reaction
adding or removing a catalyst would change the reaction rates but not
where equilibrium is
at very high temp
reactants and products may decomponse
negative delta H
exothermic
mRNA is moncistronic
meaning that each mRNA molecules translates Ito one protein product
in prok mRNA is polycistronic
mRNA can result in many different proteins depending on the lcoation
tRNA
convertingg NA to amino acid and peptides RRNA
rRNA
ribosomal machinery used during protein assembly in teh cytoplasm
the genetic code is degenerate becuaas e
more than 1 codon can specify a single amino acid
wobble position
third codon base
X^0=
1
X^-A
= 1/X^A
log 1 =
0
10^12=
tera
10^9
giga
10^6
mega
10^3
kilo
10^2
hecto
10^1
decta
10^-1
deci
10^-2
centi
10^-3
mili
10^-6
micro
10^-9
nano
10^-12
pico
isolated ysstem
system cannot exchange energy (heat and work) or matter with teh surroundings
closed system
the system can exchange energy (heat and work) but not matter with teh surroundings
open system
both energy and matter can exchange with surroundings
first law of thermodynamics
delta U = Q-W
u= change in internal energy
Q= heat added
W= work done by the system
change in internal energy is equal tot eh amount of heat transferred minus energy trsnadfered from work
if intneral E is positive, then increasing temperature, heat flows int eh system and work is done by teh system (expansion)
if negative internal E, decreasing temp, heat flow out of system and work is done on the system (compression)
isothermal processes
constant temperature so u is constant
(temperature and interval energy are directly proportional)
so Q=W
(in the delta U = Q-W equation)
Hyperbolic curve of pressure adn volume with work underneath that cuve
adiabatic processes
when no heat exchange between the system and the environment so thermal energy is constant
Q=0
delta U= -W (work done on the system)
also hyperbolic on the graph
isobaric processes
when the pressure of the system is constant.
flat lien on the P and V graph
isovolumeric process
isochoric. experience no change in volume
gas neither expands nor compresses so no work is preformed so
U=Q
vertical line on PV graph
standard conditions
25 degrees C (298k), 1 atm pressure, 1 M concentrations
BU STTANDARD TEMP AND PRESSURE IS 0 DEGREES C (IDEAL GAS)
phase changes
melting and freezing (crystallization and solidification) occur at boundary between solid and liquid
vaporization (evaporation or building) and condensation
occur at liquid and gas phase
vaporization: liquid to GAS
condensation: gas to liquid
sublimation and deposition occur at
solid and gas phase
solid to gas: sublimination
gas to solid: deposition
between liquid and gas phases is the
critical point- where liquid and gases are indigustushable
at the triple point
all three phases exist at equilibrium (the center of the graph)
phase diagram
qshows each phases according to pressure and temperature
temperature
is a scaled measured of the average kinetic energy of a substance
heat
transfer of energy that results from differences of temperature between 2 substances
the heat content of a system undergoing heating, cooling or phase changes is the
sum of all energy changes
process of a systematic absorbing heat
endothermic
Q>0
process of system release heat
exothermic
Q<0
enthaloy
is equivalent to heat (Q) oder constant pressure
q=
mc delta T MCAT m- mass c- specific heat of substance q=heat delta T= temp
specific heat
amount of energy required to raise the temp one gram of suabyance by 1 degrees C
specific heat of water
1 or 4.184
during phase changes (solid to liquid or liquid to gas), we cannot use mCAT cuz delta T is 0
q=ml
q=heat
m=mass
l- latent heat-enthalpy (heat of fusion or heat of vaporization)
when going from solid to liquid, the changes of enthalpy will be
negative because heat is removed
enthalpy
measure of the PE of a system in intermolecular attractions and chemical bonds
=U + PV
=Q-W + PV
heat, work done by the system,
Hess’s law
the total change of PE of a system is = to the changes of PE of individual steps int eh processes
second law of thermodynamics
energy spontaneously disperses from being localized to becoming spread out if it is not hindered from doing o
entropy
measure of sponetous dispersal of energy at specific temperatures
DELTA S = Q rev (heat that is gained or lost in a reversible process)/T (temp)
J/mol K
always greater than 0
when energy is distributed in a system at a given temp
entropy increases
delta G= delta H-T delta S
Gibbs free energy equation
delta H positive and delta S potivie
sponteous at high T
delta H positive and Delta S neg
nonspotous at all T
delt H neg and delta s pos
sponteous at all T
both delta H and delta S neg
sponetous at low T
boiling is an
endothermic process and delta H is motive
abd delta S is positive
delta G reaction
-RTlnKeq
R- ideal gas constant
T-temp in Kelvin
Keq- equilibrium connate `
gases have highest entropy
solids have the lowest
gases are
least dense, easily compressible
1 tm =
760 mmHg-760 torr=101 kPA = 1.013 Pa
mercury barometer
measures atm pressure
as pressure increases more mercury forced into column, increasing its height
STP
273 K (0 C) and 1 atm 1 mol of gas occupies 22.4 L
equations for ideal gases assume negligible mass and volume of
gas molecules
regardless of identity of gas, equimolar amounts of 2 gases will
occupy the same volume at the same temrpature and pressure
ideal gas law
a moleucle with no intermolecular forces and occupy no volume
PV=NRT
n- number of moles
R- ideal gas constant which is 8.21 x 10^-2
C to Kelvin
add 73
pressure of 380 mmHg
divide it by 760 mmHG to get atm
grams to moles
use molar mass (mols/g)
density
ratio of mass/volume =PM (molar mass)/RT
combined gas law
P1V1/T1=PV/T
avogadros principle
all gases are at a constant temperature and pressure occupy volumes that are directly proportional to the number of moles present
n1/V1=n2/V2
mols of gas /volume `
Boyles law
PV=PV
inverse relationship I
Charles Law
V/T= V/T
direct relationship
Gay Lussac
P/T=P/T
direct relationship
law of partial pressure
individual gas components of. MIXTURE OF GASES WILL EXERT INDIVIDUAL pressures in proportion to their mole frctions
total pressure of mixture of gases is equal tot eh sum of their partial pressure of many gases
partial pressure of a gas
Pa (pressure of A)=XPt (total pressure)
X- moles of gas A/total moles of gas
KE=
1/2mv^2
kinetic molecular theory
gases are made up of particles with low volume
gases have no intermolecular attractions or repulsions
gas are random, collisions
collisions are elastic (conversation of momentum and KE)
avg KE of gases are proportional to temp
photoelectric efect
when light of high Frequency (blue to UV light) is shown on a metal vacuum, metal atoms emit electrons. these electrons will produce a net charge flow (current)
larger intensity means
greater current and the greater the number of photons per unit time and greater number of electron per unit time
current is proportional to
intensity (amplitude) of the light