post lab discussion 5, 6 & 7 Flashcards
which literally means “color writing,” is a method of separating the components of a mixture
chromatography
chromatography is widely used for _______ and _______ analyses or for isolation and recovery of the components of a mixture
qualitative
quantitative
it is the result of chromatography
chromatogram
is the instrument used to conduct chromatography
chromatograph
what are the common types of chromatography
liquid chromatography
gas chromatograph
high performance liquid chromatography
liquid chromatography is also called
column chromatography
identify the type of chromatography:
it is generally used to separate compounds of low volatility
liquid chromatography
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
high performance liquid chromatography
identify the type of chromatography:
term used to describe the group of analytical separation techniques used to analyze volatile substances in the gas phase.
gas chromatography
Chromatography is a method by which a mixture is separated by distributing its components between _______.
2 phases
which phase in the chromatography remains fixed in place
stationary phase
identify the phase in chromatogram:
carries the components of the mixture through the medium being used
mobile phase
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
stationary phase
in a thin layer chromatography
glass, metal or plastic plates are coated with a _______ serve as the stationary phase
thin layer of adsorbent
paper wick is also known as the
filter paper
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
saturate
solvent vapour
in chromatography,
it is an absorbent of TLC plate
silica gel
in chromatography,
the tiny spots ensures the cleanest separation and does not lead to large tailing spots and poor separation
spotting
it is an equipment used where the compounds usually appear as dark spots
uv lamp
what are the 2 visualization technique for chromatography
uv lamp
iodine visualization
is is a way to visualize colorless
organic compounds that uses their
adsorption of iodine (I2) vapor
iodine visualization
Rf
retardation factor
The best data are obtained from
chromatograms in which the spots are less than ___ mm in diameter.
5
it is the ratio of the distance each compound has traveled on the plate relative to the distance the solvent has traveled
retardation factor
in chromatography, in finding a suitable developing solvent:
you should use a _______ solvent for nonpolar compounds and a
________ solvent for polar compounds
nonpolar developing
polar developing
A solvent that does not cause any compounds to move from the original spot is ________
not polar enough
a solvent that causes all the spotted material to move with the solvent front is ______
too polar
An appropriate solvent for a TLC analysis gives Rf values of ______ , with ideal values in the range ________
0.20-0.70
0.30-0.60
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
most polar - alkanes
least polar - carboxylic acid
in relative compounds of common TLC solvents and organic compounds, which common developing solvent is most polar and the least polar
most polar - alkanes, cycloalkanes
least polar - water
is caffeine strong or weakly polar
weakly polar
how many grams of caffeine will dissolve in 100ml of water
2.18g
how many grams of caffeine will dissolve in 100ml of _______
18.2
dichloromethane
what is the Rf formula
distance traveled by compound /
distance traveled by developing solvent front
what are the samples used in the reactions of aldehydes and ketones
formaldehyde
benzaldehyde
acetone
what kind of reaction is jones test
oxidation
jones test tests for
aldehydes
what are the reagents used for jones test
chromic acid
what color is the reagent of jones test
dark orange
what is the positive result of jones test
production of blue to green colored product
chromic acid is composed of ____ dissolved in _______
potassium dichromate (K2Cr207)
concentrated sulfuric acid (H2SO4)
what kind of reaction is tollens test
oxidation of aldehydes
tollens test tests for
aldehydes
what are the reagents for tollens test
silver oxide (Ag2O)
ammonium hydroxide (NH4OH)
true or false
should the reagents for tollens test be fresh
true
what is the positive result for tollens test
formation of silver mirroe
iodoform test tests for
methyl ketones
what are the reagents used in iodoform test
iodine (I2)
potassium iodide (KI)
what is the positive result for iodoform test
formation of yellow ppt
2,4-DNP test tests for
aldehydes and ketones
what are the reagent used in 2,4-DNP test
2,4-dinitrophenylhydrazine reagent
what color is the reagent of the – 2,4-dinitrophenylhydrazine reagent
orange
what is the positive results of – 2,4-DNP test
formation of yellow or orange ppt
esters are _____ group that contain _____ group bonded to the carbonyl C atom
carbonyl
alkoxy (OR’)
OR’
alkoxy
esters are abbreviated as _____
RCOOR’ or RCO2R’
carboxylic acid + alcohol =
ester + water
