MCAT Chemistry 2 Flashcards
ex of a closed syst
steam radiator
____________ is a meas of the averag ke of the particles in a syst
temperature
G is ?
free energy
bond e or bond dissoc e is?
averag of the energy req to break a part type of bond in one mole of gaseous molec
give an ex of an isolated system?
insulated bomb reactor
T or Fit is not poss to meas H directly
T
system
partic part of universe being studied
open system is?
can exch matter and e with surroundings.
ΔG <0 means a proc can?
occur spont
qrev/T =
ΔS
conversion of C (diamond) to C (graphite) is __________ but its rate is slow
spont
bond ____________ is always endothermic
breakage
stand heat of format of a compound is?
enthalpy ch that would occur if one mole of a comp were formed direct from its elem in their standard states
T or Fheat and temp are different
t
boiling has a ____________ in entropy
increase
state functions
prop that dep only on initial and final states of the system
E or U is?
internal energy
the react quotient Q is=
Q=[C]^c[D]^d/[A]^a[B]^b
units of heat?
joules
ΔH ΔS Outcome ?- +
spontaneous at all temperatures
heat changes at const press, is
enthalpy
isothermal process is?
temperat of systm is const
a system undergoes a process when?
when one or more of its prop change
ΔH ΔS + +
spontaneous only at high temperatures
-RTlnKeq =
ΔG
system can be?
isolatedclosedopen
ΔH ΔS - -
spontaneous only at low temperatures
t or fentropy is a state function
T
t or frate of a react dep on ΔG
f
for hesses law, if you multiply the prod and react by 3 ( or a cert number) then what must you do to ΔH?
also multiply it by 3
endothermic react?
absorb e
q=mc chTc is?
specific heat
q=mc chTq is?
heat
T or FΔHreact=Hprod-Hreact
T
enviroment
everthing outside system
freezing has a ___________ in entropy
decrease
a spontaneous react may or may not?
proceed to completion
bomb calorimeter, the overall system is?
adiabatic
standard free energy of format of a comp is?
free energy ch that ocurs when 1 mol of a comp in its stand form
ΔHf of an element in its standard state is?
zero
second law of thermodyn says that?
all spont proceed so that entropy of the systm plus its surr increases
temp is?
a measure of average ke of particles in a systm
name 7 state funct?
tempvolenthalpyentropyfree energyinternal energy E and U
H is?
enthalpy
what condit are heat changed measured under?
const vol calorimetryconst press calorimetry
enthalpy of a process does not depend on the?
path
rate of a reac depends on?
activat e
standard condit in thermody must not be confused with?
standard temperature and pressure in gas laws STP
closed system is?
can exch e but not matter
ΔH ΔS + -
nonspontaneous at all temperatures
isobaric process is?
press of systm is const
q react + q water + q steel=0 in a ?
bomb calorimeter
Goose hunters take shotguns reminds you of?
ΔG=ΔH-TΔS
discuss when water boils in terms of ch in G
TchS> chH only when T is above 373 K
reverse reaction has the same __________ as that of the forward react, but its ________ is oppos
enthalpy,but its sign is oppos
for simple diatomic molec such as H2, bond dissoc e can be easily measured?
spectroscopically using react E=hv E=bond dissoc e and v is freq of light absorbed
ΔS= ?/T
qrev/T
when a react commences ΔG=?
ΔG= ΔG° + RTlnQ
calorimetry measures?
heat changes
spectroscopy can be used to measure the bond dissoc e of?
simple diatomic molecules
standard free energy ΔG is ?
ΔG of a proc occur at 25 C and 1 atm . concentr of sol are 1 M
ΔS=Sfin- Sinit
Sfin- Sinit
standard heat of react is?
ΔHreact= (sum of ΔHf of prod)-(sum of ΔHf of react)
exothermic react?
release e
a system undergoes a ____________ when one or more of its properties change
process
standard state of a subs is the form a subst takes?
at 25 C and 1 ATM
Hess law says?
that enthalpies of react are additive
heat absorbed by a system is?
pos
Thermodynamics
- Is the study of energy and it’s relationship to macroscopic properties of chemical systems. It’s functions are based on probabilities and are only valid for systems that are composed of a large number of molecules.* I.e The rules of thermodynamics gov
System vs. Surroundings
A system is a part of a universe that is the macroscopic body under study, and the surroundings is everything else.Systems are based on mass and energy exchange with the surroundings. There are three systems:1) open: exchange both mass and energy with surroundings.2) closed: Exchange energy but not mass3) isolated: Do not exchange energy or mass.
State Function
A state is the physical condition of a system described by a specific set of thermodynamic property values. Such properties that describe the state of a system are called State Functions.Two types of properties used to describe the state of a system: 1) Extensive: properties are propotional to the size of the system (eg. V + n)2) Intensive: are independent of the size of the system. ( eg. P + T )Seven State Functions: U (internal Energy), T, P, V, H (Enthalpy), S (entrophy) and G (Gibbs energy).
Heat
(q)Heat has three forms:1) Conduction2) Convection3) RadiationAlways the movement of energy from hot to cold.
Work
work = P∆V
Convection
- Is the thermal energy transfer via fluid movements.- differences in density or pressure drive warm fluid to cold fluid*Oceans and air currents are commone examples of convection.
Radiation
- is thermal energy transfer via electromagnetic waves. (eg. heated metal red, orange, white, blue-white)- All objects above 0K radiate heat.P= σ∈AT⁴
The First Law of Thermodynamics
∆E = q + w*Warning: work ON the system is positive for “convention” a passage on MCAT may define work done BY the system as a postive in which case you use this formula.
The Second Law of Themodynamics
*See heat engines
Internal Energy Types
MCAT may refer to internal energy as “heat energy”, “thermal energy,” or even “heat.”“Heat energy and thermal energy” are really the vibrational, rotational and translational parts of interanl energy. Called this because they effect temperature.”Heat” is a transfer of energy. Don’t mistake.
Temperature
0 K = 273°C
Enthalpy
(H) = is a man- made property that accounts for this extra capacity to do PV work. Unlike functions such as pressure, volume , and temperature, enthalpy is not a measure of some intuitive property. Defined more so as an equation then a property:H≡ U + PV
Standard State
- Don’t confuse with STP. STP is at 0°C whereas standard state is at 25°C and is arbritrarily assigned an enthalpy value of 0 J/mol
Reference Form
Define
Standard Enthalpy of Formation
Define
Exothermic vs. Endothermic
Define
Activation Energy
Define
Transition state
Define
Intermediates
Define
Catalyst
Define
Irreversible vs. reversible reactions.
Define
Third law of Thermodynamics
Define
Spontaneity
Define
Gibbs Free Energy
Define
Thermodynamics
- Is the study of energy and it’s relationship to macroscopic properties of chemical systems. It’s functions are based on probabilities and are only valid for systems that are composed of a large number of molecules.* I.e The rules of thermodynamics gov
What are two ways to transfer energy between systems
NAME?
Conduction
- is thermal energy transfer via molecular collisions.- Requires direct physical contact- an objects ability to conduct heat is called it’s thermal conductivity (k) **On page 46 go over again.Q / t = kA [ T(h) - T(c) ) / L ]
Stephan- Boltzman Law
P= σ∈AT⁴Where:A is the surface area of the objectT is the temperatureσ is the Stefan- Boltzman constant (5.67 x 10⁻⁸ )∈ is the emissivity of the object’s surface.
Zeroth Law of Thermodynamics
Discovered after 1st, 2nd, and 3rd Law of Thermodynamics. All three rely on this Law, as it is based off of temperature.States: Two systems in thermal equilibrium with a third system are in thermal equilibrium with each other. The law declares that the two bodies in thermal equilibrium share a termodynamic property, which must be a state function. This is temperature.
Standard Temperature and Pressure
(STP)
Mean free path
Define
Ideal gas
Define
Kinetic Molecular theory
Define
Ideal gas law
PV = nRTK.E.(avg) = 3/2 (RT)
Standard Molar volume
22.4L —> At STP one mole of any gas (behaving ideally will occupy this amount.
Partial Pressure
Pa= Xa Ptotal
Dalton’s Law
P (total) = P1 + P2 + P3 …
Graham’s Law
v1/v2 = √M2 / √M1
Effusion
effusion rate 1/ effusion rate 2 = √M2 / √M1
Diffusion
Define
Chemical Kinetics
Define
Collision Model
Define
Activation Energy
Define
The effect of temperature on the rate of reaction
The rate of a reaction increases with temperature
Intermediates
Define
Rate Law
Define
Order of each respective reactant
Define
Overall Order of a reaction
Define
Rate Determining Step
Define
Catalyst
Define
Heterogeneous catalyst
Define
Homogeneous Catalyst
Define
Chemical Equilibrium
Define
Equilibrium Constant
K
The law of Mass Action
Define
Reaction Quotient
Define
Le Chatelier’s Principle
Define
Metals
- large atoms that tend to lose electrons and form positive ions (cations) to obtain a noble gas configuration.- Can bond with other metal atoms (metallic bonding)- can also form ion bonds with negative ions (anions) *Usually non-metals.-Metals are
Ductile
- easily stretched.- occurs in metals- if you stretch or hammer e- the metals can adapt (which is why you can stretch metal without breaking them)
Luster
NAME?
Non- metals
- form negative ions (anions) to obtain a noble gas configuration.- form covalent bonds with other non-metals- form ionic bonds with positive ions (usually metals)- poor conductors of heat and electricity- non-malleable, brittle and possess low to moder
Metalloids
NAME?
Transition metals
- wont be focused on for MCAT, just know that they exist and that this might be a passage based question.- 1/2 vs fully filled orbitals occur here often.
Alkaline Earth Metals
- Harder metallic sollids have 2 valence electrons (can easily form +2 cations)- have a higher melting point than solf metallic solids- Heavier are more reactive than lighter ones.
Halogens
F₂: gas at RT and 1 atmCl₂: gas at RT and 1 atmBr₂: liquid at RT and 1 atmI₂: solid at RT and 1 atm* all highly reactive unless in diatomic form.-7 valence e-
Noble gases
- 8 valence e– complete octet so very stable and non-reactive.
How do you determine the number of valence electrons in a main group atom?
- look at the group numberif group 1= 1 e- on valence shell (+1)group 2= 2 e- on valence shell (+2)recall: First shell closest to nucleus = ground stateLast shell closest to outside world = Valence e- shell. *Valence e- are involved in chemical bonding
Atoms
Define
Protons
Define
Electrons
Define
Nucleus
Define
Neutrons
Define
Elements
Define
Mass Number
(A)
Atomic Number
(Z)
Isotopes
Define
Atomic Weight
Define
Molar Mass
(MM or M)
Atomic Mass Units
(amu)
Mole
Define
Avogadro’s Number
Define
Periodic Table
Define
Period
Define
Groups or Families
Define
Metals
Define
Nonmetals
Define
Metalloids
Define
Transition Metals
Define
Inert Gases
Define
Shields
Define
Effective Nuclear Charge
(Z eff)
Periodic trends
Define
Atomic Radius
Define
Ionization Energy
Define
Second Ionization Energy
Define
Electronegativity
Define
Electron affinity
Define
Metallic Character
Define
Bonds
Define
Covalent Bonds
Define
Bond Length
Define
Bond Energy
*Or bond dissociation energy
Compound
Define
Empirical Formula
Define
Molecules
Define
Molecular formula
Define
Ionic Compounds
Define
Acids
Define
Binary Molecular compounds
Define
Physical reaction
Define
Chemical reaction
Define
Runs to completion
Define
Fundamental Reaction types
1) Combination: A+B —> C2) Decomposition: C —> A + B3) Single Displacement: A + BC –> B + AC4) Double Displacement: AB +CD —> AD + CB
Principle Quantum Number
(n)*Note: quantum numbers are the equivalent of a mailing address for an electron.- Description: Energy level and average distance from nucleus- Possible values: n= 1, 2, 3 etc.
Shell
Define
Valence electrons
Define
Azimuthal Quantum number
(l)*Also known as angular momentum quantum numberDescription: Orbital shape (s, p, d, f)Possible values: l=0, to …n-1l=0 is the s-subshelll=1 is the p-subshelll=2 is the d-subshelll= 3 is the f-subshell
Subshell
eg. s, p, d and fs= sphericalp= dumbbell shapedd= clover leaf
Magnetic Quantum number
m- Description: Orbital orientation (px, py, pz)- Possible values: m= -l to +lfor l=0 (spherical s orbital) there is only one orientation.for l=1 (dumbbell p orbital_ there are three orientations along each of the x, y, and z axes.
Atomic Orbital
Space around a nucleus in which e- have the ability to exist.- max 2 e- in each orbital.
Electron Spin quantum Number
m (s)- Description: Describes spin of electron- Possible values: m(s) = +½ or -½Either clockwise or counter clockwise.
Pauli exclusion Principle
NAME?
Heisenberg Uncertainty Principle
- tells us that the exact position and momentum of such an electron cannot be measure simultaneously. *Ie the more you know about the momentum of an electron, the less you know about it’s exact position.
Aufbau Prinicple
*Write out on a piece of paper before writing mcat.1s2s 2p3s 3p 3d4s 4p 4d 4f5s 5p 5d 5f6s 6p 6d7s 7p
Electron Configuration
Know 5 points on page 29 of lecture manual.
Ground State
Define
Hund’s Rule
Define
Planck’s Quantum theory
Define
Photoelectric effect
- an important experiment demonstrating the particle nature of light. An electron can be ejected from the surface of a metal by shining light of a certain frequency. Incoming light (photon) must have enough energy to eject the electron.E(photon) = h(Plank
Wavelength vs. Frequency vs. Velocity
Wavelength = distance btwn two consecutive crests of troughs. measured in meters.Frequency= the number of crests that pass through a given point per unit of time (Hertz)Velocity= the distance a wave travels through space/ unit time (m/s)Frequency= (velocity) / (wavelength)
Wave particle duality
all matter, including light can be thought of as both a wave and as a particle.
Electromagnetic Radiation
(EMR) is simple energy. as energy travels forward electric and magnetic fields are created perpendicular to each other and to the direction of travel.