sep pro chaps 1 to 3

Question 1

create a second phase that is immiscible with the feed phase

Answer 1

by phase creation

Question 2

introduce a second phase in the form of a solvent

Answer 2

by phase addition

Question 3

restrict or enhance the movement of certain chemical specie

Answer 3

by barrier

Question 4

add solid particles that act directly or as an inert carriers for separation

Answer 4

by a solid agent

Question 5

applying external field of various types

Answer 5

by force field or gradient

Question 6

production requirement, cost, environmental impact

Answer 6

considerations in which separation method to choose

Question 7

involves heat transfer or shaft work to or from the mixture

Answer 7

Energy-Separating Agent

Question 8

May be partially immiscible with one or more mixture components and
frequently is the constituent of highest concentration in the added phase.

Answer 8

Mass-Separating Agent

Question 9

May be miscible with a liquid feed mixture, but may selectively alter partitioning
of species between liquid and vapor phases

Answer 9

Mass-Separating Agent

Question 10

When the feed mixture includes species that
differ widely in volatility, expressed as
vapor-liquid equilibrium ratios (K-values)

Answer 10

Partial Condensation or Partial Vaporization

Question 11

Two phases are created when a vapor feed is
partially condensed by removing heat, and a
liquid feed is partially vaporized by adding
heat.

Answer 11

Partial Condensation or Partial Vaporization

Question 12

In both operations, after partitioning of species has
occurred by interphase mass transfer, the resulting vapor
phase is enriched with respect to the species that are
more easily vaporized, while the liquid phase is enriched
with respect to the less-volatile species, with both phases
separated by gravity

Answer 12

Flash Vaporization

Question 13

Partial vaporization can be initiated by this method
by reducing the feed pressure with a valve or turbine.

Answer 13

Flash Vaporization

Question 14

When the volatility difference among species
are so small (more than 100 trays are
required). Mass-separating agent (MSA) is used to
increase the volatility difference (reducing the
number of trays)

Answer 14

Extractive Distillation

Question 15

In extractive distillation, ______ is thee least volatile species
and is introduced ______________of the column.

Answer 15

MSA, near the top

Question 16

in extractive distillation, what do they do to minimize MSA loss?

Answer 16

Recycle

Question 17

When volatility difference among species are not
sufficiently large and it is the most widely used industrial separation technique

Answer 17

Distillation

Question 18

Multiple contact between counter-current flow of
V/L in trays (stages). Each contact (stage) consists of mixing the
phases to promote rapid partitioning of species by
mass transfer, followed by phase separation.

Answer 18

Distillation

Question 19

When condensation of vapor is not easily
accomplished, a liquid MSA (adsorbent)
may be fed to the top in place of reflux.

Answer 19

Reboiled Absorption

Question 20

iquid mixtures are separated,
at elevated temperature &
ambient pressure, by
contacting the feed with a
vapor stripping agent (MSA)

Answer 20

Stripping

Question 21

If the feed is vapor and the
stripping section of the
column is not needed

Answer 21

Absorption

Question 22

The MSA eliminates the need
to reboil the liquid at the
bottom of the column, which
may be important of the liquid
is not thermally stable.

Answer 22

Stripping

Question 23

If the bottoms product from
a stripper is thermally
stable, it may be reboiled
without using an MSA.

Answer 23

Reboiled Stripping

Question 24

If trays are needed above
the feed tray to achieve
separation

Answer 24

Refluxed Stripping

Question 25

Another term for Refluxed Stripping

Answer 25

Steam Distillation

Question 26

When minimum-boiling azeotropes are formed

Answer 26

Azeotropic Distillation

Question 27

What is an MSA for Azeotropic distillation?

Answer 27

n-butyl acetate

Question 28

what are the two products in azeotropic distillation?

Answer 28

distillate water layer and bottoms acetic acid

Question 29

When distillation is impractical, especially when the mixture to be separated is temperature-sensitive.

Answer 29

liquid-liquid extraction

Question 30

Each solvent has a specific selectivity for the feed components. Several countercurrently arranged stages may be necessary

Answer 30

Liquid-Liquid Extraction (Two-Solvent)

Question 31

A solvent selectively dissolves only one or a fraction of the components in the feed

Answer 31

Liquid-liquid extraction

Question 32

A common manufacturing step since many chemicals are processed wet but sold as dry

Answer 32

Drying

Question 33

The vapor pressure of the liquid to be evaporated from the solid be higher than its partial pressure in the gas stream.

Answer 33

Drying

Question 34

In addition to the effects of such external conditions as temperature, humidity, air flow, and degree of solid subdivision on drying rate, the effects of internal diffusion conditions, capillary flow, equilibrium moisture content and heat sensitivity must be considered.

Answer 34

Drying

Question 35

The transfer of volatile components of a liquid into a gas by heat transfer

Answer 35

Evaporation

Question 36

Give at least 2 applications of evaporation

Answer 36

Humidification, air conditioning, concentration of aqueous solutions

Question 37

Describe sublimation

Answer 37

The transfer of species from the solid to the gaseous state without the formation of an intermediate liquid phase.

Question 38

Applications: separation of sulfur from impurities, purification of benzoic acid, and freeze-drying of foods

Answer 38

Sublimation

Question 39

Two or more soluble species are separated by partial freezing

Answer 39

Melt Crystallization

Question 40

A versatile melt-crystallization technique which relies on selective distribution of impurities between a liquid and a solid phase

Answer 40

Zone Melting or Refining

Question 41

The mixture, which includes a solvent, is cooled and/or the solvent is evaporated

Answer 41

Solution Crystallization

Question 42

A purification step, so the conditions must be such that impurities do not precipitate with the product

Answer 42

Crystallization

Question 43

Carried out in some organic, and in almost all inorganic, chemical plants where the desired product is a finely divided solid.

Answer 43

Crystallization

Question 44

The reverse of sublimation. The sublimed gas, unlike water, does not puddle

Answer 44

Desublimation

Question 45

Separates gas or liquid mixtures by passing them through a packed bed

Answer 45

Chromatography

Question 46

what chromatography uses bed that are solid particles?

Answer 46

gas-solid chromatography

Question 47

a bed that is a solid-inert support coated with a viscous liquid

Answer 47

gas-liquid chromatography

Question 48

A macromolecule (a ligate) is selectively adsorbed by a ligand (e.g. an ammonia molecule in a coordination compound)

Answer 48

Affinity Chromatography

Question 49

Resembles adsorption in that solid particles are used and regenerated. However, a chemical reaction is involved.

Answer 49

Ion Exchange

Question 50

In water softening, an organic or inorganic polymer in its sodium form removes calcium ions by a calcium-sodium exchange.

Answer 50

Ion Exchange

Question 51

After prolonged use, the (spent) polymer, saturated with calcium, is regenerated by contact with a

Answer 51

concentrated salt solution

Question 52

Give 3 separation methods in of separation by solid agent.

Answer 52

adsorption, chromatography, ion exchange

Question 53

Can take advantage of the differing degrees of response of molecules and ions to force fields

Answer 53

Separation by External Field or Gradient

Question 54

Based on the fact that molecular diffusion can be caused by a temperature gradient.

Answer 54

Thermal Diffusion

Question 55

Takes advantage of even tiny differences in density to separate various particles in a solution

Answer 55

Centrifugation

Question 56

In a solution, particles whose density is higher than that of the solvent sink (sediment), and particles that are lighter than it float to the top

Answer 56

Centrifugation

Question 57

A method of separating bonded elements and compounds by passing an electric current through them.

Answer 57

Electrolysis

Question 58

Transport ions from one solution through ion-exchange membranes to another solution under the influence of an applied electric potential difference

Answer 58

Electrodialysis

Question 59

A cation- and anion-permeable membranes carry a fixed charge, this preventing migration of species of like charge

Answer 59

Electrodialysis

Question 60

Exploits the different migration velocities of charged colloidal or suspended species in an electric field

Answer 60

Electrophoresis

Question 61

Positively charged species, such as dyes, hydroxide sols, and colloids, migrate to the cathode, whilst small, suspended, negatively charged particles go to the anode.

Answer 61

Electrophoresis

Question 62

Components of the mixture travel in the flow direction at different velocities, so a separation is achieved. An electrical or magnetic field or thermal gradient is established perpendicular to a laminar-flow field

Answer 62

Field-Flow Fractionation

Question 63

3 stages of field-flow fractionation

Answer 63

injection, relaxation, separation

Question 64

Used in the metallurgical, natural product, and food industries.

Answer 64

Leaching or Liquid-solid extraction

Question 65

A natural or chelate-induced surface activity cause a solute to migrate to rising bubbles and is thus removed as foam.

Answer 65

Foam Fractionation

Question 66

Use of microporous/nonporous membrane as semipermeable barriers for selective separations

Answer 66

Separation by Barrier

Question 67

: Separation is effected by rate of species diffusion through the pores

Answer 67

Microporous membrane

Question 68

Separation is controlled by differences in solubility in the membrane and diffusion rate of species through the membrane

Answer 68

Nonporous membrane:

Question 69

give the different membrane materials

Answer 69

natural fibers, synthetic polymers, ceramics, metals, liquid films

Question 70

give the different fabrication of membrane

Answer 70

flat sheets, tubes, hollow fibers, spiral-wound sheets

Question 71

Give the driving force, membrane pore size, separation mechanism of the you know na

Answer 71

(refer to the table )

Question 72

differentiate osmosis and reverse osmosis. which one is spontaneous and explain why.

Answer 72

Involves transfer, by a concentration gradient, of a solvent through a membrane into a mixture of solute and solvent, Transport of solvent in the opposite direction is effected by imposing a pressure, higher than the osmotic pressure, on the feed side

Question 73

nvolves separation of solutes by diffusion across the membrane from one liquid phase to another liquid phase, on the basis of molecular size and molecular conformation

Answer 73

Dialysis

Question 74

Transport by a concentration gradient of small solute molecules, sometimes called crystalloids, through a porous membrane

Answer 74

Dialysis

Question 75

Species transported through the nonporous membrane is evaporated to achieve high purities

Answer 75

Pervaporation

Question 76

First used in the 1940s with porous fluorocarbon barriers to separate 235UF6 and 238UF6 T, requiring enormous amount of electric power

Answer 76

Gas Permeation

Question 77

Only a few molecules thick and can be formed from surfactant-containing mixtures at the interface between two fluid phases

Answer 77

Liquid Membrane

Question 78

Used to remove species in low concentrations and is followed by desorption to regenerate adsorbents

Answer 78

Adsorption