Module 6: SIMPLE DISTILLATION AND CHROMATOGRAPHY

Question 1

• involves the process of “separating two or more liquids” homogenously mixed but with different boiling points (at least 20 degrees difference)

Answer 1

SIMPLE DISTILLATION

Question 2

• when the mixture of liquids to be distilled is heated, the “liquid with the _________ boiling point” turns into vapors first

Answer 2

lowest

Question 3

• as the distillation progresses, the concentration of the lowest boiling component will ___________

Answer 3

steadily decrease

Question 4

• when the temperature again stabilizes, another pure fraction of the distillate can be collected

Answer 4

fractional distillation

Question 4

• further acidification of the previous reaction of acetone with sodium nitroprusside and sodium hydroxide using acetic acid will convert the wine-red color into _______________, thereby confirming the distillate as acetone (as elaborated by Le Nobel)

Answer 4

magenta-red solution

Question 5

• as the solution starts to boil, the liquid with the ______ boiling point turns to vapors first

Answer 5

lowest

Question 5

• this vapor would then be “condensed back into
  liquid” inside the condenser, which will then be
  collected as the ________

Answer 5

distillate

Question 6

lowering the pressure, thus, lowering the boiling point of the
substance

Answer 6

note!

Question 6

separation of the liquid mixture can be detected through _______

Answer 6

ignition test

Question 6

• an organic sample (acetone) will ignite, thereby can identifying what type of compound is the ____________

Answer 6

distillate

Question 7

acetone (a ketone) will react with sodium nitroprusside and sodium hydroxide producing a ________________ due to the formation of acetone nitroprusside ion complex

Answer 7

wine-red solution

Question 7

react with acetone (a ketone) producing a wine-red solution

CH3COCH3 + Na2[Fe(CN)5NO] [Fe(CN)5NO(CH2COCH3)] NaOH2+

Answer 7

SODIUM NITROPRUSSIDE TEST

Question 8

reaction of acetone with sodium nitroprusside and sodium hydroxide using _____________ will convert the wine-red color into magenta-red solution

Answer 8

GLACIAL ACETIC ACID

Question 9

• the process of separating the substances in a complex mixture by their “different affinities” to an “adsorbent”

Answer 9

CHROMATOGRAPHY

Question 9

• derived from the Greek words, chroma meaning _____, and graphein meaning to _______

Answer 9

chroma = color
graphein = write

(literally means color writing)

Question 9

Chromatography commonly used for analyzing mixtures of
______________

Answer 9

colored chemicals

Question 9

• this technique involves separation of constituent elements of the mixture

Answer 9

Chromatography

Question 10

Chromatography invented by a Russian botanist, _________________, in 1901, while researching on plant pigments

Answer 10

Mikhail Semyonovich Tsvet

Question 11

• a liquid or solid that is fixed in a place during the process

Answer 11

STATIONARY PHASE

Question 12

• usually a high quality filter paper, or an adsorbent

Answer 12

STATIONARY PHASE

Question 13

• either liquid or gas which moves the samples through the stationary phase during the process

Answer 13

MOBILE PHASE

Question 14

• solvent or a mixture of solvents

Answer 14

MOBILE PHASE

Question 15

components of the sample will separate readily according to how strongly they “__________ on the stationary phase” versus how readily they “________ in the mobile phase”

Answer 15

1. adsorb
2. dissolve

Question 15

• organic compounds interact with adsorbents at different
  ___________________

Answer 15

rates and interaction

Question 16

- it can only have weak Van der Waals forces of attraction for the adsorbent

Answer 16

non-polar

Question 17

interacts through "dipole-dipole interactions or hydrogen bonding"

Answer 17

polar

Question 17

_________________ absorb strongly on stationary phase (adsorbent)

Answer 17

polar compounds

Question 18

__________ will be only weakly absorbed, and thus, has higher affinity with the mobile phase (solvent)

Answer 18

non-polar compounds

Question 18

the extent of separation is measure by the _______________

Answer 18

retention factor or the Rf value

Question 19

Rf value depends on the _____________ and _______________ of the components of the sample

Answer 19

1. relative solubility 2. adsorptive properties

Question 20

𝑅𝑓 𝑣𝑎𝑙𝑢𝑒 formula

Answer 20

𝑅𝑓 𝑣𝑎𝑙𝑢𝑒 = 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑡𝑟𝑎𝑣𝑒𝑙𝑙𝑒𝑑 𝑏𝑦 𝑡ℎ𝑒 𝑠𝑢𝑏𝑠𝑡𝑎𝑛𝑐𝑒 -------------------------------------------------- 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑡𝑟𝑎𝑣𝑒𝑙𝑙𝑒𝑑 𝑏𝑦 𝑡ℎ𝑒 𝑠𝑜𝑙𝑣𝑒𝑛t

Question 21

_____________ draws a developing solvent up the TLC plate

Answer 21

capillary action

Question 21

involves a stationary phase made up of an adsorbent (silica gel) coated over an "inert solid plate" (usually aluminum), and a mobile phase made up of a "solvent system" (mixture of appropriate solvents)

Answer 21

THIN LAYER CHROMATOGRAPHY

Question 22

the adsorbent will also ______________ part or all the mixture (as more solvent comes by, the mixture will again go into solution, move further and be reabsorbed)

Answer 22

reabsorb

Question 22

* as this solvent pass through the spot, the "mixture will be ________" and will begin to "move with the solvent front"

Answer 22

dissolved

Question 23

* largely depends on adhesion and cohesion forces which allows the mobile phase to move along the stationary phase due to surface tension

Answer 23

PAPER CHROMATOGRAPHY

Question 23

passage of the solvent front through the adsorbent is known as _____________

Answer 23

developing the plate

Question 23

Paper Chromatography largely depends on __________ and __________

Answer 23

adhesion and cohesion forces

Question 24

SIMPLE DISTILLATION = DISTILLATE B temperature:? compound:? polarity:? ignition test:? rxn with Na nitroprusside:? rxn with acetic acid:?

Answer 24

temperature: collected at ~100°C compound: water polarity: polar ignition test: no ignition rxn with Na nitroprusside: light pink color rxn with acetic acid: yellow color

Question 24

* the paper is placed inside a ____________

Answer 24

closed chamber/container

Question 25

* it is important that the solvent level is __________ with samples

Answer 25

below the spots

Question 25

container should be covered during the process

Answer 25

prevent volatilization

Question 25

PAPER CHROMATOGRAPHY AMINO ACID: glycine THEORETICAL Rf VALUE:?

Answer 25

0.57

Question 25

spraying the paper with a solution that reacts with the sample allows ___________

Answer 25

visualization of the spots

Question 25

the paper is _______________ and then just stands in the bottom of the container

Answer 25

coiled or formed into cylinder

Question 25

_________ solution reacts with amino acids giving colored compounds usually brown or purple known as _____________

Answer 25

1. ninhydrin 2. Ruhemann’s purple

Question 26

SIMPLE DISTILLATION = DISTILLATE A temperature:? compound:? polarity:? ignition test:? rxn with Na nitroprusside:? rxn with acetic acid:?

Answer 26

temperature: collected at ~57°C compound: acetone polarity: non-polar ignition test: burn with luminous flame rxn with Na nitroprusside: wine red color rxn with acetic acid: magenta red color

Question 26

PAPER CHROMATOGRAPHY AMINO ACID: lysine THEORETICAL Rf VALUE:?

Answer 26

0.53

Question 27

PAPER CHROMATOGRAPHY AMINO ACID: phenylalanine THEORETICAL Rf VALUE:?

Answer 27

0.91