post lab discussion 5, 6 & 7

Question 1

which literally means “color writing,” is a method of separating the components of a mixture

Answer 1

chromatography

Question 2

chromatography is widely used for _______ and _______ analyses or for isolation and recovery of the components of a mixture

Answer 2

qualitative
quantitative

Question 3

it is the result of chromatography

Answer 3

chromatogram

Question 4

is the instrument used to conduct chromatography

Answer 4

chromatograph

Question 5

what are the common types of chromatography

Answer 5

liquid chromatography
gas chromatograph
high performance liquid chromatography

Question 6

liquid chromatography is also called

Answer 6

column chromatography

Question 7

identify the type of chromatography:
it is generally used to separate compounds of low volatility

Answer 7

liquid chromatography

Question 8

identify the type of chromatography:
separates compounds dissolved in a liquid sample and allows qualitative and quantitative analysis of what components and how much of each component are contained in the sample

Answer 8

high performance liquid chromatography

Question 9

identify the type of chromatography:
term used to describe the group of analytical separation techniques used to analyze volatile substances in the gas phase.

Answer 9

gas chromatography

Question 10

Chromatography is a method by which a mixture is separated by distributing its components between _______.

Answer 10

2 phases

Question 11

which phase in the chromatography remains fixed in place

Answer 11

stationary phase

Question 12

identify the phase in chromatogram:
carries the components of the mixture through the medium being used

Answer 12

mobile phase

Question 13

identify the phase in chromatogram:
acts as a constraint on many of the components in a mixture, slowing them down to move slower than the mobile phase

Answer 13

stationary phase

Question 14

in a thin layer chromatography
glass, metal or plastic plates are coated with a _______ serve as the stationary phase

Answer 14

thin layer of adsorbent

Question 15

paper wick is also known as the

Answer 15

filter paper

Question 16

filter paper three-quarters of the way around the inside of the developing chamber to help ______ its atmosphere with_______ by wicking solvent into upper region chamber

Answer 16

saturate
solvent vapour

Question 17

in chromatography,
it is an absorbent of TLC plate

Answer 17

silica gel

Question 18

in chromatography,
the tiny spots ensures the cleanest separation and does not lead to large tailing spots and poor separation

Answer 18

spotting

Question 19

it is an equipment used where the compounds usually appear as dark spots

Answer 19

uv lamp

Question 20

what are the 2 visualization technique for chromatography

Answer 20

uv lamp
iodine visualization

Question 21

is is a way to visualize colorless
organic compounds that uses their
adsorption of iodine (I2) vapor

Answer 21

iodine visualization

Question 22

Rf

Answer 22

retardation factor

Question 23

The best data are obtained from
chromatograms in which the spots are less than ___ mm in diameter.

Answer 23

5

Question 24

it is the ratio of the distance each compound has traveled on the plate relative to the distance the solvent has traveled

Answer 24

retardation factor

Question 25

in chromatography, in finding a suitable developing solvent: you should use a _______ solvent for nonpolar compounds and a ________ solvent for polar compounds

Answer 25

nonpolar developing polar developing

Question 26

A solvent that does not cause any compounds to move from the original spot is ________

Answer 26

not polar enough

Question 27

a solvent that causes all the spotted material to move with the solvent front is ______

Answer 27

too polar

Question 28

An appropriate solvent for a TLC analysis gives Rf values of ______ , with ideal values in the range ________

Answer 28

0.20-0.70 0.30-0.60

Question 29

in relative compounds of common TLC solvents and organic compounds, which organic compounds by functional group class is more polar and which is less polar

Answer 29

most polar - alkanes least polar - carboxylic acid

Question 30

in relative compounds of common TLC solvents and organic compounds, which common developing solvent is most polar and the least polar

Answer 30

most polar - alkanes, cycloalkanes least polar - water

Question 31

is caffeine strong or weakly polar

Answer 31

weakly polar

Question 32

how many grams of caffeine will dissolve in 100ml of water

Answer 32

2.18g

Question 33

how many grams of caffeine will dissolve in 100ml of _______

Answer 33

18.2 dichloromethane

Question 34

what is the Rf formula

Answer 34

distance traveled by compound / distance traveled by developing solvent front

Question 35

what are the samples used in the reactions of aldehydes and ketones

Answer 35

formaldehyde benzaldehyde acetone

Question 36

what kind of reaction is jones test

Answer 36

oxidation

Question 37

jones test tests for

Answer 37

aldehydes

Question 38

what are the reagents used for jones test

Answer 38

chromic acid

Question 39

what color is the reagent of jones test

Answer 39

dark orange

Question 40

what is the positive result of jones test

Answer 40

production of blue to green colored product

Question 41

chromic acid is composed of ____ dissolved in _______

Answer 41

potassium dichromate (K2Cr207) concentrated sulfuric acid (H2SO4)

Question 42

what kind of reaction is tollens test

Answer 42

oxidation of aldehydes

Question 43

tollens test tests for

Answer 43

aldehydes

Question 44

what are the reagents for tollens test

Answer 44

silver oxide (Ag2O) ammonium hydroxide (NH4OH)

Question 45

true or false should the reagents for tollens test be fresh

Answer 45

true

Question 46

what is the positive result for tollens test

Answer 46

formation of silver mirroe

Question 47

iodoform test tests for

Answer 47

methyl ketones

Question 48

what are the reagents used in iodoform test

Answer 48

iodine (I2) potassium iodide (KI)

Question 49

what is the positive result for iodoform test

Answer 49

formation of yellow ppt

Question 50

2,4-DNP test tests for

Answer 50

aldehydes and ketones

Question 51

what are the reagent used in 2,4-DNP test

Answer 51

2,4-dinitrophenylhydrazine reagent

Question 52

what color is the reagent of the – 2,4-dinitrophenylhydrazine reagent

Answer 52

orange

Question 53

what is the positive results of – 2,4-DNP test

Answer 53

formation of yellow or orange ppt

Question 54

esters are _____ group that contain _____ group bonded to the carbonyl C atom

Answer 54

carbonyl alkoxy (OR')

Question 55

OR'

Answer 55

alkoxy

Question 56

esters are abbreviated as _____

Answer 56

RCOOR' or RCO2R'

Question 57

carboxylic acid + alcohol =

Answer 57

ester + water