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Test 2- Ch.6
Multiphase Systems
29
Chemical Engineering
Undergraduate 2
03/25/2011

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Cards

Term
Clausius-Clapeyron Equation***look up in lecture
Definition

ln(p*) = -(heat of vaporization per mole)/(R*T) + B

where ln(p*) is y

(1/T) is x

-(heat of vap. per mole)/R is m

 

also: ln(P2)-ln(P1) = ((Hvap)/R)*((1/T1)-(1/T2))

 

 

Term
Delta Heat of Sublimation
Definition
Delta Heat of Sublimation = Delta Heat of Fusion + Delta Heat of Vaporization
Term
Antoine Equation
Definition

log10(p*) = A - (B/(T+C))

were T is in degrees C and p* is in mmHg

Term
Gibbs Phase Rule
Definition

DF = The number of independent intensive properties that must be specified to determine all other intensive properties for a system. 

DF = 2 + C - pi - r

C = number of chemical species

pi = number of phases in a system at equilibrium

r = independent reactions of system components

Term
Intensive Property
Definition
Does not depend on the size of the system: e.g. temperature, pressure, specific volume, density, or mole fraction
Term
Superheated Vapor
Definition
when p(i) = y(i)*P < p*(i)(T)
Term
Degrees of Superheat
Definition
The difference between the temperature and the dew point of the gas 
Term
Dew Point of a Gas
Definition
The temperature at which the vapor becomes saturated.
Term
Raoult's Law for a Single Condensable Species
Definition

p(i) = y(i)*P = p*(i)(T)

partial pressure of the substance = the vapor pressure of the substance at that temperature

Term
boiling point
Definition
where p*=P
Term

Relative Saturation/

Relative Humidity

Definition
(sr or hr) = (pi/p*i(T))*100%
Term

Molal Saturation/

Molal Humidity

Definition
(sm or hm) = (pi/(P-pi)) = moles of vapor/ moles of vapor-free (dry) gas
Term

Absolute Saturation/

Absolute Humidity

Definition

(sa and ha) = (pi*Mi)/((P-pi)Mdry) =

mass of vapor/mass of dry gas

Term

Percentage Saturation/

Percentage Humidity

Definition
(sp or hp) = (pi/(P-pi))/(p*i/(P-pi*)) * 100%
Term
Raoult's Law
Definition

xi.p*i = yi.P

 

Term
Raoult's Law Limitations
Definition

-Applies to ideal solutions

-applies to real solutions if xi approaches 1

-also for solutions of substances with similar MWs and structures

Term
Henry's Law
Definition

pa = ya*P = xa*Ha

where Ha is a constant

-valid for solutions were xa is close to 0, dilute solutions 

Term
Bubble Point Temperature
Definition
P = sigma(xa.p*a(Tbp))
Term
Bubble Point Pressure
Definition
yi = pi.P(dp) = (xi.p*i(T)/P(bp))
Term
Dew Point Temperature
Definition

xi = (yi.P)/(p*i(Tdp)) 

where i = A,B,C..excluding G

Term
Dew Point Pressure
Definition
Pdp = 1/[(ya/p*a(T)) + (yb/p*b(T))+...]
Term
Change in Boiling Point
Definition
delta(Tb) = [(R*T(bo)^2)/Hv]*x
Term
Change in Melting Point
Definition

delta(Tb) = [(R*T(mo)^2)/Hm]*x

Term

Distribution Coefficient

(e.g. chloroform/water)

Definition

K = (x)c phase/(x)w phase

x = mass fraction of solute

Term

Equilibrium of 2 partially miscible solvents/

Liquid-Liquid Extraction

Definition
if two product streams are in equilibrium, their compositions must lie on the phase envelope and must be connected by a tie line
Term
Langmuir Adsorption Isotherm
Definition

xi = a.K.pi/(1+ K.pi)

xi = grams adsorbate/grams adsorbent

pi= partial pressure of adsorbate

a,K are constants

adsorbate = component attracted to the solid surface of the adsorbent

Term
Flashing
Definition
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