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    Generalization of Ideal Gas Behavior

    Boyles Law

    The volume of any definite quantity of

    gas at constant temperature varied

    inversely as the pressure on the gas.

    P1V1 = P2V2

    Charles Law

    The volume of a definite quantity of

    gas at constant pressure is directly

    proportional to the absolute temperature.

    Gay-Lussacs Law

    Combined Gas Law

    Avogadros Law

    Ideal Gas Equation

    PV = nRT

    Values of R:

    0.08205 L-atm/mol-K

    82.05 cc-atm/mol-K

    8.314 x 107 ergs/mol-K

    8.314 J/mol-K

    1.987 cal/mol-K

    62360 mmHg/mol-K

    Daltons Law of Partial pressure

    At constant temperature, the total

    pressure exerted by a mixture of gases in a

    definite volume is equal to the sum of the

    individual pressure without each gases

    would exert if it occupied the same total

    volume alone.

    PT = P1 + P2 + P3 + +Pn

    Partial pressures:

    P1 = P2 =

    P3 =

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    Daltons Law:

    PT =

    PT = nT

    Partial Pressure of a gas to the total

    pressure of the mixture:

    P1 =

    P2 =

    P3 =

    PA/PT = nA/nT = NA (mole fraction)

    PB/PT = nB/nT = NB (mole fraction)

    PC/PT = nC/nT = NC (mole fraction)

    NA + NB + NC = 1

    Amagats Law of Partial Pressure

    In any gas mixture the total volume

    may be considered to be the sum of the

    partial volumes of the constituents of the

    mixture.

    VT = V1 + V2 + V3 + + Vn

    V = (n1 + n2 + n3)

    V = nT

    VA/V = NA/RT = NA

    VB/V = NB/RT = NB

    VC/V = N

    C/R

    T= N

    C

    Graham's Law of Diffusion

    At constant temperature and pressure,

    the rate of diffusion of various gases

    varies inversely as the square roots of

    their densities or molecular weights.

    =

    =

    Where:

    u or r = rate of diffusion

    p1 or p2 = densities

    Limitation of Ideal Gas

    Low to moderate pressurePV = znRT

    Where:

    z = compressibility factor

    If: z > 1 = dominant adhesive force

    z < 1 = dominant cohesive force

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    Van Der Walls Equation of State

    Van Der Walls deduced that the

    magnitude of the pressure correction P' for

    n moles of gas present in volume V is given

    by:

    P' = where a is a constant

    Thus:

    (P +

    (V-nb) = nRT

    Note: valid only for wide pressure range

    a =

    b =

    Kamerlingh Onnes Equation of State

    PV seriesPVm = A + BP + BP2 + BP3 +

    Where:

    P = pressure

    Vm = molar volume

    A,B,C = viral coefficients

    Rate: PVM = A

    PV2 = nRT

    Berthelot Equation

    PV = nRT (1 +

    Where: T = actual temperature

    Tc = critical temperature

    P = actual pressure

    Pc = critical pressure

    Beattie - Bridgeman Equation of State

    P =

    Vm =

    Where:

    = RTB0 - A0 -

    = -RTB0b + Aoa -

    =

    T = absolute temperature

    R = gas constant

    Ao, Bo, a, b, c = constant

    characteristic of each gas

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    Molecular Weights of Gases

    p = p =

    MW = M =

    Some Methods for Determination of Molecular

    Weights

    Regnult's Method

    > employed to determine the molecular

    weights of substances which are gaseous at

    room temperature.

    Dumas' Method

    > used to determine molecular weights

    in the vapor phase of readily volatile

    liquids.

    Wvapor = W(bulb + vapor) - W(bulb + air) + Wair

    M =

    [1 +

    (1- )] (Berthelot

    Equation)

    Determination of ExactMolecular Weights

    Method of limiting densities

    > based upon the fact that as zero

    pressure is approached, the ideal gas laws

    become the exact for all gases

    PMW = pRT

    p/P = MW/RT = constant

    (p/P)P=0 = MW/RT

    MW = RT P=0

    Plotting:

    P (atm)

    Kinetic Theory of Ideal Gases

    The Kinetic Theory is based on the

    following fundamental postulates:

    1. Gases are considered to be composed of

    minute discrete particles called molecules.

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    For any one gas all molecules are thought

    to be of the same mass and size but to

    differ in these from gas to gas.

    2. The molecules within a container are

    believed to be in ceaseless chaotic motion

    during which they collide with each other

    and with the walls of the container.

    3. The bombardment of the contaiuner walls

    by the molecules gives rise to thephenomenon we call pressure (force/unit

    area).

    4. In as much as the pressure of the gas

    within a container does not vary with time

    at any given pressure and temperature. The

    molecular collisions must involve no energy

    loss due to friction. In other words, allmolecular collisions are elastic.

    5. The absolute temperature is a quantity

    proportional to the average kinetic energy

    of all the molecules in a system.

    6. At relative low pressures, the average

    distances between molecules are largecompared with the molecular diameters, and

    hence the attractive forces between

    molecules, which depend on the distance of

    molecular separation, may be considered

    negligible.

    7. Finally, since the molecules are small

    compared with the distances between them,

    their volume may be considered to benegligible compared with the total volume

    of the gas.

    Root-Mean-Square Velocity

    U =

    = Where:

    U = root-mean-square velocity

    Ux, Uy, Uz = component velocities along

    x, y, or z

    Momentum = mass x velocity (mu)

    Change in momentum

    m = m1 - m2

    = mux - (-mux) = 2mux

    Change in Momentum per Second per Moleccule

    = (2mux) =

    = 2

    Total change in momentum/molecule/second =

    2

    + 2

    + 2

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    = (U

    2x + U2y + U2z)

    = U2

    For n' molecules in a cube

    Total change in momentum per second =

    P = =

    P = =

    =

    PV = mn'

    Where:

    A cube = 6l2

    F =

    V = l3

    Deductions from Kinetic Theory of Gases

    Boyle's Law

    1/2 mn'U2 = K1T

    1/2 PV = 1/3 K1T

    PV = 2/3 K1T

    PV = C

    V/T = C'

    P/T = C"

    Charle's Law

    V = T

    V = K2T

    Avogadro's Principle

    > equal volumes of all gases at the same

    pressure and temperature contain equal

    numbers of molecules

    For two gases

    P1V1 = P2V2

    1/3 n'1m1= 1/3 n'2m2

    m1 = m2

    per mole

    1/3 n'1m1= 1/3 n'2m2

    n'1 = n'2

    n' = n x avogadros number

    where:

    n = moles

    n' = molecular wt

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    N'1 = N'2 (no of molecule will be the

    same)

    Avogadro's No (N) = 6.023x1023 molecules/gram-

    mole

    Graham's Law of Diffusion

    PV = C

    P1V1 = P2V2

    1/3 n'1m1= 1/3 n'2m2

    U21/ U22 =

    U1/ U2 = =

    U1/ U2 = = =

    PV = nRT

    PV = 1/3 n'mu2 = nRT

    PV = = nRT

    Where:

    n' = nM

    n' = no of molecules

    n = avogadro's number

    Further Deduction from the Kinetic Theory

    Velocity of Gas Molecules

    > 1/3 nMWU2 = nRT

    U2 =

    U =

    = Kinetic Energy of Translation

    Ek =(

    nMu

    2)

    =nRT

    Where:

    nRT =

    MWU2 = 3RT

    On division by Avogadro's no.

    Ek/N =

    = kT

    Where:

    K = is called the Boltzman constant

    and is equal to 1.3805 x 10-16 erg per

    degree

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    Distribution of Molecular Velocities

    Maxwell-Boltzman Distribution Law

    dnc/n' = 4(

    )3/2 e-MC2/2RT c2dc

    dividing by dc:

    P =

    = 4(

    )

    3/2 e-MC2/2RT c2dc

    W

    here:

    P = probability of finding molecules

    with the velocity

    dnc = no of molecules out of a total

    n' having velocities between c and c + dc

    M = molecular wt

    T = temeperature of gas

    Dnc/n' = fraction of the total number of

    molecules having the same velocities

    Most Probable Velocity ()

    = Average Velocity (v)

    = v = 0.912u

    v = 0.921 where:

    :v:u = 1:1.128:1.224

    Frequency of Collisions and Mean Free Path

    > the number of molecules which a single

    gas molecule will collide per second is:

    v2(n*)2

    Where:

    v = average velocity in cm per second

    = molecular diameter in cm

    n* = n x (6.023 x 1023)

    Z = v2(n*)2

    Z = total no of colliding molecules per cc

    per second

    Nc = no of molecular collisions occurring

    in each cc per second

    Nc =

    =

    v

    2(n*)2

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    Mean Free Path (l)

    > the average distance a molecule traverse

    before colliding

    l =

    Heat Capacity of Gases

    Cp = at constant pressure

    Cv = at constant volume

    Ek = RT

    E = Ek2 - Ek1 =R(T2 -T1)

    Cp - Cv =

    Cv = R

    Cp = R

    H = E + PV

    Specific Heat Ratio

    For monoatomic gases:

    = =

    = = 1.667

    For diatomic gases: (H2, N2, O2 I2 Cl2)

    Cp - Cv = R Cp = 7/2 R

    Cv = 5/2 R = 1.4

    For triatomic gases: (CO2, SO2, H2S N2O)

    = 1.3

    Theory of Non-Ideal Gases

    Interaction energy (E')

    E' = - +

    Force interaction (f')

    f' = -

    where:

    A and B are constant molecule

    r = distance of separation

    n = constant whose value may range from

    9 12

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    LIQUIDS

    Critical Phenomena in Liquids

    > properties of liquids and vapor become

    identical

    > critical points are:

    Critical Temperature, Tc

    Critical Pressure, Pc

    Critical Volume, Vc

    For H2O critical constants are:

    Tc = 374.4C

    Pc = 219.5 atm

    Vc = 58.7 cc per mole

    Liquefaction of Gases

    Process involve: cooling

    Cooling + compressor

    For permanent gases:

    Adiabatic expansion, Q = 0

    Allowing gas to cool itself by performing

    work in adiabatic expansion against piston.

    Viscosity

    > resistance to flow and produce by

    shearing effect of moving one layer of

    fluid past, another and quite distinct from

    intermolecular attraction.

    Fluidity > opposite of viscosity

    =

    Where:

    =

    = viscosity on absolute

    dynamic

    Kinematic Viscosity

    Viscosity of Gases

    = vlp

    where:

    p = density

    l = mean free path

    l =

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    Poiseville or Stokes Equation

    =

    1/2 =

    Where:

    P = pressure

    t = time of flow

    r = radius of tube

    V = volume of liquid

    Stoke's Law

    > applicable to the fall of spherical

    bodies in all types of fluid media provided

    the radius of the falling body is large

    compared with the distance between the

    molecules of the fluid.

    W = m g/gc

    W = PV g/gc

    F1 = 4/3 r3(p - pm)g/gc

    F2 = 6rv

    Equating F1 and F2:

    4/3 r3(p - pm)g/gc = 6rv

    =

    Fluidity ()

    =

    1/2 =

    > the viscosity of liquid decreases withincreasing temperature

    Fg = F1

    FR = F2

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    First Law of Thermodynamics

    Thermodynamics = study of energy conversion

    Kinds of Energy

    > Kinematic Energy

    The energy a system possesses by

    virtue of its motion

    > Potential Energy

    The energy a system possesses by

    virtue of its position

    Mechanical energy > erg (cgs)

    Electrical energy > joule (cgs)

    Thermal energy > calorie (cgs)

    Thermodynamic System

    System

    > anything under study or consideration

    > as any portion of the universe isolated

    on or in an inert container, which maybe

    real or imaginary, for purposes of study of

    the effect of various variables upon the

    contents of the system.

    A system can be:

    Open System

    > flow of energy, flow of mass (pump)

    > a system which can exchange both matter

    and energy with its surroundings

    Closed System

    > no mass flow, flow of energy (elec bulb)

    > one which no transfer of matter to or

    from the surroundings is possible, but that

    of energy is

    Isolated System

    > no mass flow(transfer): no energy flow

    > one which cannot exchanged both matter

    and energy with its surroundings

    It can be:

    Homogeneous System = contains only one

    phase

    Heterogeneous System = two or more

    than a single phase may involved

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    Phase

    > defined as homogeneous, physically

    distinct, and mechanically separable

    portion of a system.

    Steady State

    > does not change in time

    True Solution

    > physically homogeneous mixture of two or

    more substances

    Thermodynamics SystemProperties:

    Extensive property

    > dependent on the mass

    Intensive Property

    > mass independent

    First Law of Thermodynamics

    Energy can neither be created nor

    destroyed but it can only transform from

    one form to another.

    PE1 + KE1 + E1 + P1V1 + Q = W + P2V2 + KE2 +E2 +

    P2V2

    First Law Equation:

    E = q - W

    dW = fdl = pAdl

    W =

    Wmax is attained at reversible process

    W = (+) work is done by the system (V2 > V1)

    expansion

    W = (-) work is done on the system (V2 < V1)

    compression

    q = (+) absorbed

    q = (-) evolved

    E = q - p(V2 - V1)

    a. P is constant

    E = q - p(V2 - V1)

    b. Volume is constant

    E = q

    c. free expansion

    P = 0; W = 0

    E = q

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    d. P is variable, T is constant

    W = nRT ln

    W = nRT ln

    Enthalpy of a System

    H = E + PV

    H = H2 - H1

    = (E2 + P2V2) - (E1 + P1V1)

    = (E2 - E1) + (P2V2 - P1V1)

    = E + P(V2 - V1)

    H = E + PV

    Where:

    E = internal energy

    If Cp = f(T)

    Cp = a + bT + CT2 + dT3

    Cp = a + b/T2 + C/T2

    H = n

    At constant volume:

    C =

    Cv = (

    v

    =

    E =

    E = mCvT

    H = E

    H = (E2 - E1) + (P2V2 - P1V1)

    H = E + Pv

    H = q - PV + PV

    H = q

    H > E if w = 0, w > 0

    H = E if w = 0

    H = (+) absorption of heat

    H = (-) evolution of heat

    0

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    Heat Capacity (Cp, Cv)

    Cp = heat capacity at constant temperature

    W = rate of change of the internal energy

    with temperature at constant volume.

    Cp = (

    v

    At constant pressure:

    Cp = (

    P

    If Cp is constant:

    H = nCpT

    =

    H = when n = 1

    H = when n = 1

    H = E + PV

    Differentiating it with respect to

    temperature at constant pressure:

    Cp - Cv = ()P + P(

    ) - (

    )v

    Difference of state of state function on

    variables:

    *E as a function of (T, V) then:

    E = f(T,V)

    *H = f(T,P)

    dH = CpdT + [V - T()P]dP

    Thermodynamics Behavior of Ideal Gas

    PV = nRT

    For ideal gas:

    Cp - Cv = nR

    Cp - Cv = R

    For monoatomic gases:

    Cp = 5/2 R

    Cv = 3/2 R

    For diatoimic gases:

    Cp = 7/2 R

    Cv = 5/2 R

    Note:

    =

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    For monoatomic = 1.6

    For diatomic = 1.4

    For triatomic = 1.3

    Isothermal andAdiabatic Process

    Isothermal Processes

    > any process conducted in a manner such

    that the temperature remains constant

    during the entire operation.

    E = q - w

    0 = q - w

    q = w

    Isothermal process in ideal gas

    W = nRT ln V2/V1

    W = nRT ln P1/P2

    If P is constant:

    W = P(V2 - V1)

    Adiabatic process in ideal gas

    q = 0 (no heat evolved nor absorbed)

    E = - w

    w = - E

    Where:

    E =

    * Gas laws are not applicable in adiabatic

    process.

    Derived formula:

    P1V1 = P2V2

    = ( )

    = (

    = (

    w =

    w =

    Joule - Thompson Effect

    Adiabatic:E = - w

    E2 - E1 = (P2V2 - P1V1)

    E2 + P2V2 = E1 + P1V1

    H2 = H1

    H = 0

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    Joule - Thomson Coefficient:

    =()H

    Cp = - ()T

    Cp = T ()P - V

    Where:

    Cp = ()P

    = 0 at inversion point (gas

    neither heat or cools)= (+) cooling

    = (-) heating

    The Carnot Cycle

    > in itial and final states are equal

    > composed of several steps/processes

    Carnot Cycle Steps

    > 2 isothermal (T = C) process (expansion,

    compression)

    > 2 adiabatic process (q = 0) (expansion,

    compression)

    Analysis of the cycle

    1. AB --- isothermal expansion

    E = q2 - w1

    E = 0

    q2 = w1 = nRT2 lnV1/V2 = nRT lnP2/P1

    w = q2 - q1

    2. BC --- adiabatic expansion

    q = 0

    E = - w2

    E =

    3. CD --- isothermal compression

    E3 = 0

    E3 = -q1 - w3

    q1 = -w3 = -nRT lnV4/V3

    4. DA --- adiabatic compression

    q = 0

    E4 = -w4

    E4 =

    E cycle = 0

    w max = q2 - q1

    P

    V

    Isothermal

    Expansion

    AdiabaticExpansion

    Isothermal

    Compression

    Adiabatic

    Compression P1V1

    P2V2

    P3V3

    P4V4

    A

    B

    C

    D

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    Thermodynamics Efficiency

    Eff =

    x 100Eff =

    =

    =

    = x 100

    =

    x 100

    ThermoChemistry

    > branch of physical chemistry which deals

    with the thermal changes accompanying

    chemical and physical transformation.

    Heat lost = heat gained

    qH = mCpT

    Heat of ReaCTION AT Constant Volume or

    Pressure

    E = q - w

    q = E +

    at constant volume: V = 0q = E

    at constant pressure:

    q = H

    where:

    H + E = (+) heat is absorbed

    H + E = (-) heat is evolved

    Calculation of E fromH or vice versa

    H = E + PV

    = E + (PVP - PVR)

    = E + (npRT -nRRT)

    = E + (NP -NR) RT

    H = E + ngRT

    Where: ng = nP - nR

    Hess' Law of Heat Summation

    > the heat of reaction must be independent

    of the particular manner in which the

    reaction takes place

    Heat of Combustion

    > for combustible material

    > amount of heat liberated per mole of

    substance burned

    Hrxn =

    Heat of Formation

    > heat involved in the formation of 1 mole

    of substance from the element.

    Kirchhoff's Equation

    Cp = CpP - CpR

    Cp = [

    ]P

    E2 =

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    The Second and Third Law of Thermodynamics

    > The flow of heat is unidirectional,always from higher temperature region to

    lower temperature region.

    > All naturally occurring process always

    tend to change spontaneous in a direction

    which will land to equilibrium.

    > Heat cannot be converted to work which

    leaving permanent changes either in systems

    involved or in their surroundings.

    Haber Process

    Entropy

    > degree of disorder

    > state of a function> depends only on initial and final state

    of the system

    S = S2 - S1

    dS =

    where dq = infinite quantity of heat

    At constant temperature:

    =

    S =

    Entropy Change in Isolated Systems

    Reversible expansion:

    Ss =

    Sr =

    V1 - V2 System = Ss + Sr

    = +

    System = 0

    Isolated System Under Non-Isothermal

    Condition Founds:

    > for any reversible process or cycle S =

    0

    > for any irreversible process or cycle

    S = ; S > 0

    The Second Law of Thermodynamics

    > All process in nature tend to occur only

    with an increase in entropy and that the

    directions of change is always such as to

    the entropy increase.

    dsi > 0

    T2

    q2

    q1

    W

    q2 = q1 + W

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    Entropy Change for Systems Only

    ds = ds + dsr > 0system + reservoir

    dsr =

    ds + dsr > 0 E = q - w

    ds - > 0 dE = dq - dw

    Tds - dq > 0 dq = dE + dw

    Tds - dE - pdV -dw' > 0

    For irreversible process

    Tds - dE - PdV - dw' > 0

    PV = nRT P = P1 dw' = dw'mTds - dE - PdV - dw;mx = 0

    Tds - dE - PdV = 0

    Entropy Change in Ideal Gases

    Isothermal

    dE = 0Tds = PdV

    ds =

    ds =

    =

    In Isolated System

    S = nRln

    S = nRln

    S = -nRln

    Dependence on Temperature andVolume

    ds = (

    )v dT + (

    )T dV

    = dT +

    )vdV

    S = nCv ln

    + nR ln

    S = f (T,P)

    S = ncP ln

    + nR ln

    Entropy of Mixing for Ideal Gas

    Sm = n1R ln

    + n2R ln

    Sm = n1R ln

    + n2R ln

    If

    =

    = PT (special cases)

    Sm = - (n1RlnN1 + n2RlnN2)

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    Entropy Change in Physical Transformations

    S = S2 - S1

    S = =

    where: Hv = latent heat

    q = Hv = Hf = Hs

    Hs = Hv + Hf

    L - G S =

    (evaporation)

    G - L S = (cooling)S - L S =

    (melting)

    S - G S = =

    (sublimation)

    q = sensible heat

    q = mCpT

    Change Entropy in Chemical Reactions

    A + bB + = cC + dD +

    S = -

    S = ;

    =

    S2 = S1 + nCpln

    if cP is constant

    Third Law of Thermodynamics

    -

    ST =

    ST =

    Free Energy and Equilibrium

    > capability of the rxn to do work

    Helholtz Free Energy (A)

    A = E - TS

    At constant temperature:

    A = A2 -A1

    = (E2 -TS2) - (E1 - TS1)

    = E - T(S2 - S1)

    A = E - T(S)

    If T is not constant:

    A = (E2 -TS2) - (E1 - TS1)

    = E - (T2S2 - T1S1)

    A = E - TS

    S =

    qr = TS

    At constant temperature:

    A = E - TS

    = E - qr

    = - wWmax = -A

    Where: in first law of thermodynamics

    E = q - w

    E - q = - w

    At constant temperature; ideal gas

    W = nRT ln

    = nRT ln

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    A for Reactions

    A = E - TS

    dA = dE - (TdS + SdT)

    A = f (T,V)

    a) dA = ()vdT + (

    )dV

    b) dA = dE - TdS - SdT

    = dE - SdT - dqr

    Where:

    dqr = dE + dw

    dqr = dE + pfV

    dA = dE - SdT - (dE + pdV)

    dA = - SdT - pdV

    Where:

    -S = (

    )v A = E - TS

    -P = ()T

    Therefore:

    ()v =

    =

    (

    )v = -

    ()v =

    dT

    Where:

    E = f(T)

    E =

    ()v =

    dT

    The Gibbs Free Energy (G)

    G = H - TS

    G = G2 -G1

    G = H - TS if T is constant

    G = H - qr

    = E + PV - qr

    = E - qr + PV

    = A + PV

    G = A + PVG = - (Wm - PV)

    Where:

    A = f (T,V)

    G = f (T,P)

    G1 = (H1 - T1S1) = G2

    G = A + PV

    S =

    A = - w

    E = q - w

    E - q = A

    G = f (T, P)

    dG = VdP - SdT

    [

    ]P =

    =

    =

    (

    ) =

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    Where:

    -S = ()P

    V = ()T

    G = H - TS

    H = G + TS

    ( )P = - S

    (

    ) =

    Properties and Significance of G

    AT constant T, P:

    G = 0 @ equilibrium

    G = - spontaneous

    G = + non - spontaneous

    G = H - TS

    G = H - qr

    qr = H - G

    qr (+) = H >G (absorbed)

    qr (-) = G >H (evolved)

    Calculations of Free Energy Changes

    At constant temperature:

    G = VP if V is constant

    If V = f (T) ; ideal gas

    G = nRT ln

    G = nRT ln

    Fugacity andActivity Concepts

    G = RT lnf + B

    At standard state:

    G0 = RTlnf0 + B

    G = G0 + nRT ln f/f0

    G = G0 + 1

    G = G0

    Per Mole:

    G = nRT ln

    Where:

    f/f0 = a

    a = 1

    Standard State for Gases

    Where:

    f0 = 1 f = P as P = 0

    a = f/f0 lim

    = 1

    a = f P-0

    G = G0 + RT lnf

    = (activity coefficient)

    ideal gas

    Determination of Activity Coefficients of

    Gases

    dG = VdP ; G = VP

    G = G0 + RT lnf

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    dG = RTdlnf

    dlnf =

    dlnf =

    = ( + )

    = +

    = dlnP +

    Dlnf - dlnP =

    W

    here: = V -

    V = +

    =

    dln

    = dln =

    =

    lny = (P - 0)lny =

    if T and is constant

    Standard States for Solid and Liquids

    > As the standard of pure solid or liquidis taken the solid or liquid at 1 atm

    pressure at each temperatue.

    a = 1

    The Reaction Isotherm

    A + bB cC + dD

    GA = + RT ln aA

    GB = + RT ln aB

    GC = + RT ln aC

    GD = + RT ln aD

    Grxn =

    -

    = (cGC + dGP) - (GA + bGB)G = G0 + RT ln (ln /)

    Criteria of Equilibrium

    Where:

    G = 0

    H = E + PV

    G = H - TS

    TdS = dE - PdV = 0

    If:

    V = C ; E = C

    dV = 0 ; dE = 0

    Then:

    TdS - 0 - 0 = 0

    TdS = 0

    dS = 0

    (S)E,V = 0 at equilibrium

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    If:

    T and V are constants

    dA + 0 + 0 = 0(dA)T,V = 0

    (A)T,V = 0

    Then:

    A = E - TS

    dA = dE - TdS - SdT

    TdS - dE = -dA - SdT

    -dA - SdT -PdV = 0

    dA - SdT - PdV = 0

    3 Criteria of Equilibrium

    (S)E,V = 0

    (G)T,P = 0

    (A)T,V = 0

    AT constant T and P:dG + 0 - 0 = 0

    (dG)T,P = 0

    (G)T,P = 0

    Then:

    G = H - TS

    = E + PV - TS

    G = A + PV

    dG = dA + PdV + VdP

    dA + PdV = dG - VdP

    -SdT = dG - VdP

    dG + SdT - VdP = 0

    where: A = E - TS

    Physical equilibrium Involving Pure

    Substances

    At equilibrium:

    dG = 0 dA = 0

    dT = dP = 0 A = 0

    G = 0 A2 - A1 = 0

    G2 - G1 = 0 A2 = A1

    G2 = G1

    dG = -SdT + VdP = dG1 = dG2

    -S2dT + V2dP = -S1dT + V1dP

    (V2 - V1)dP = (S2 - S1)dT

    dP/dT = (S2 - S1)/(V2 - V1) =

    Where:

    S = q/T ; q = H

    S = H/T

    Therefore: =

    --- clayperon equation

    Uses of Clayperon Equation

    =

    =

    (

    )

    =

    P2 - P1 = ln

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    The Boiling Point of Liquids

    Liquid to Vapor (Evaporation/Condensation)

    H = Hv =

    =

    Where:

    V = Vg - VL

    V = VgPV = nRT

    Vg = nRT/P

    By substitution: integration:

    ln=

    (

    )

    Solid to Liquid(Fusion)

    H = Hf where: V = Vl - Vs =

    By substitution: integration:

    P2 - P1 = ln

    Troutons Rule

    = c = 21

    Sublimation (Solid to Gas)

    Hs = Hv + Hf

    V = Vg - Vs =

    =

    By substitution and integration:

    ln

    =

    (

    )

    where:

    Vg >>> Vs

    V = Vg

    PV = nRT

    V = nRT/P

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    PhysicalChemistry

    I

    Physical

    Principles

    Alfredo Samsona Jr.