Chapter 2

Question 1

energy requirements are determined by applying

Answer 1

the first law of thermodynamics

Question 2

estimates of minimum energy needs can be made by

Answer 2

applying the second law of thermodynamics with an entropy balance or an availability balance

Question 3

it is a measure of the maximum amount of energy that can be converted into shaft work

Answer 3

availability of a stream

Question 4

loss of availability or exergy can be calculated in either of two ways

Answer 4

1 from the exergy (availability) balance
2 from the irreversible increase in the entropy of the universe

Question 5

the equivalent work of separation for an irreversible process is given by

Answer 5

the sum of lost work and minimum work of separation

Question 6

is the study of the equilibrium which exists between or within different states of matter namely solid, liquid, gas

Answer 6

phase equilibrium

Question 7

is defined as a stage when chemical potential of any component present in the system stays steady with time

Answer 7

equilibrium

Question 8

is a region where physical and chemical properties of the system are same throughout the region

Answer 8

phase

Question 9

the distribution of phases in equilibrium is determined by application of

Answer 9

the gibbs free energy

Question 10

is the starting point for the derivation of commonly used equations for expressing phase equilibria

Answer 10

gibbs free energy

Question 11

at equilibrium, the total G for all phases is a minimum, and methods for determining this minimum are referred to as

Answer 11

free-energy minimization techniques

Question 12

is the ratio of the partial fugacity of a component to its fugacity in a standard state, at a given temperature

Answer 12

activity

Question 13

partial molar gibbs free energy of species i

Answer 13

μi, chemical potential

Question 14

the chemical potential of a particular species in a multi-component system is _______ in all phases at physical equilibrium

Answer 14

identical

Question 15

is employed as a surrogate for chemical potential as it is not a favored property for phase-equilibria calculations

Answer 15

fugacity

Question 16

is a pseudo-pressure

Answer 16

partial fugacity

Question 17

used to represent departure of activities from mole fractions when solutions are non-ideal

Answer 17

activity coefficient

Question 18

is the ratio of mole fractions of a species in two phases in equilibrium

Answer 18

phase equilibrium ratio

Question 19

For vapor-liquid (V-L) systems the phase equilibrium ratio is referred to as

Answer 19

K-value or vapor-liquid equilibrium ratio

Question 20

for moderate pressures, the ______________ is introduced by approximating he pure-component liquid fugacity coefficient

Answer 20

poynting correction

Question 21

is convenient for a low-molecular-weight gas species, whose temperature at the critical point is less than the system temperature

Answer 21

Henry’s law form for the k-value

Question 22

for the liquid-liquid (L-L) systems the phase equilibrium ratio is referred to as

Answer 22

distribution or partition coefficient / liquid-liquid equilibrium ratio

Question 23

is the ratio of equilibrium ratios

Answer 23

separation factor

Question 24

for vapor-liquid systems, the separation factor is referred to as the

Answer 24

relative volatility

Question 25

for liquid-liquid systems, the separation factor is referred to as the

Answer 25

relative selectivity

Question 26

where does the simplest (EOS) model apply

Answer 26

when both liquid and vapor phases are ideal solutions (all activity coefficients equal to 1.0) and the vapor is an ideal gas

Question 27

is expressed in terms of vapor-liquid and liquid-liquid K-values, which are formulated in terms of fugacity coefficients and activity coefficients

Answer 27

phase equilibrium