post lab discussion 5, 6 & 7 Flashcards

1
Q

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

A

chromatography

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2
Q

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

A

qualitative
quantitative

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3
Q

it is the result of chromatography

A

chromatogram

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4
Q

is the instrument used to conduct chromatography

A

chromatograph

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5
Q

what are the common types of chromatography

A

liquid chromatography
gas chromatograph
high performance liquid chromatography

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6
Q

liquid chromatography is also called

A

column chromatography

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7
Q

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

A

liquid chromatography

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8
Q

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

A

high performance liquid chromatography

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9
Q

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

A

gas chromatography

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10
Q

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

A

2 phases

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11
Q

which phase in the chromatography remains fixed in place

A

stationary phase

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12
Q

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

A

mobile phase

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13
Q

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

A

stationary phase

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14
Q

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

A

thin layer of adsorbent

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15
Q

paper wick is also known as the

A

filter paper

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16
Q

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

A

saturate
solvent vapour

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17
Q

in chromatography,
it is an absorbent of TLC plate

A

silica gel

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18
Q

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

A

spotting

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19
Q

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

A

uv lamp

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20
Q

what are the 2 visualization technique for chromatography

A

uv lamp
iodine visualization

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21
Q

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

A

iodine visualization

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22
Q

Rf

A

retardation factor

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23
Q

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

A

5

24
Q

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

A

retardation factor

25
Q

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

A

nonpolar developing
polar developing

26
Q

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

A

not polar enough

27
Q

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

A

too polar

28
Q

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

A

0.20-0.70
0.30-0.60

29
Q

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

A

most polar - alkanes
least polar - carboxylic acid

30
Q

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

A

most polar - alkanes, cycloalkanes
least polar - water

31
Q

is caffeine strong or weakly polar

A

weakly polar

32
Q

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

A

2.18g

33
Q

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

A

18.2
dichloromethane

34
Q

what is the Rf formula

A

distance traveled by compound /
distance traveled by developing solvent front

35
Q

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

A

formaldehyde
benzaldehyde
acetone

36
Q

what kind of reaction is jones test

A

oxidation

37
Q

jones test tests for

A

aldehydes

38
Q

what are the reagents used for jones test

A

chromic acid

39
Q

what color is the reagent of jones test

A

dark orange

40
Q

what is the positive result of jones test

A

production of blue to green colored product

41
Q

chromic acid is composed of ____ dissolved in _______

A

potassium dichromate (K2Cr207)
concentrated sulfuric acid (H2SO4)

42
Q

what kind of reaction is tollens test

A

oxidation of aldehydes

43
Q

tollens test tests for

A

aldehydes

44
Q

what are the reagents for tollens test

A

silver oxide (Ag2O)
ammonium hydroxide (NH4OH)

45
Q

true or false
should the reagents for tollens test be fresh

A

true

46
Q

what is the positive result for tollens test

A

formation of silver mirroe

47
Q

iodoform test tests for

A

methyl ketones

48
Q

what are the reagents used in iodoform test

A

iodine (I2)
potassium iodide (KI)

49
Q

what is the positive result for iodoform test

A

formation of yellow ppt

50
Q

2,4-DNP test tests for

A

aldehydes and ketones

51
Q

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

A

2,4-dinitrophenylhydrazine reagent

52
Q

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

A

orange

53
Q

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

A

formation of yellow or orange ppt

54
Q

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

A

carbonyl
alkoxy (OR’)

55
Q

OR’

A

alkoxy

56
Q

esters are abbreviated as _____

A

RCOOR’ or RCO2R’

57
Q

carboxylic acid + alcohol =

A

ester + water