Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Chemistry (Tara) > Organic Chem 9 > Flashcards

Organic Chem 9 Flashcards

(96 cards)

Start Studying
1
Q

what is chromatography used for?

A

to separate different substances in a mixture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

principle of chromatography

A

a mobile phase will carry a dissolved mixture through a stationary phase. The separation occurs, as some of the components of the mixture tend to be held by the stationary phase and move more slowly than those that mix well with the mobile phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

mobile phase

A

a solvent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

stationary phase

A

paper or thin layer of aluminium oxide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

TO SEPARATE A MIXTURE OF INDICATORS USING CHROMATOGRAPHY

those that do not dissolve easily in the solvent

A

will come out of the solution and appear on the paper as a spot

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

TO SEPARATE A MIXTURE OF INDICATORS USING CHROMATOGRAPHY

those that dissolve well

A

will be carried up the paper further and will eventually appear as spots on the paper at different intervals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

TO SEPARATE A MIXTURE OF INDICATORS USING CHROMATOGRAPHY

how to get results

A

by finding Rf values

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

TO SEPARATE A MIXTURE OF INDICATORS USING CHROMATOGRAPHY

Rf=

A

distance travelled by solvent front

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

TO SEPARATE A MIXTURE OF INDICATORS USING CHROMATOGRAPHY

first step

A

solvent added to the bottom of the glass jar, to a depth of about 1 cm and allow to stand for a while

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

TO SEPARATE A MIXTURE OF INDICATORS USING CHROMATOGRAPHY

why do you allow to stand

A

to allow the tank to become saturated with the solvent’s vapour

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

TO SEPARATE A MIXTURE OF INDICATORS USING CHROMATOGRAPHY

what do you do to the paper

A

make a line near the top with a pencil and another near the bottom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

TO SEPARATE A MIXTURE OF INDICATORS USING CHROMATOGRAPHY

next step - making a small concentrated spot of mixture

A

a small spot of mixture of indicators was placed on the line with a capillary tube and dried with a hair dryer. repeat several times

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

TO SEPARATE A MIXTURE OF INDICATORS USING CHROMATOGRAPHY

putting paper into jar

A

place in glass jar with spot side down, do not immerse spot, paper just touches solvent, attach paper to glass rod using sellotape

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

TO SEPARATE A MIXTURE OF INDICATORS USING CHROMATOGRAPHY

everything is set up

A

allow to run until the solvent reached the line at the top of the paper

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

TO SEPARATE A MIXTURE OF INDICATORS USING CHROMATOGRAPHY

when solvent reaches top

A

paper is removed and dried

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

TO SEPARATE A MIXTURE OF INDICATORS USING CHROMATOGRAPHY

what does not allow for accurate results?

A

the particles of the stationary phase are not small and uniform in size 1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

USING THIN LAYER CHROMATOGRAPHY

what do TLC plates have the stationary phase as

A

a layer of aluminium oxide or silica gel spread thinly and evenly over aluminium foil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

USING THIN LAYER CHROMATOGRAPHY

what does the foil provide

A

support for the stationary phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

USING THIN LAYER CHROMATOGRAPHY

why is it more efficient than paper chromatography

A

the particles in the stationary phase are smaller and uniform in size, more accurate separation of the components in the mixture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

USING THIN LAYER CHROMATOGRAPHY

what speeds up saturation of jar with solvent

A

a piece of filter paper was cut to fit around the walls of the glass jar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

USING THIN LAYER CHROMATOGRAPHY

what was first added?

A

industrial methylated spirits was added to allow it to saturate the paper and give a depth of about 1cm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

USING THIN LAYER CHROMATOGRAPHY

after spirits added

A

jar is covered and let stand for a wile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

USING THIN LAYER CHROMATOGRAPHY

what do you do the plate

A

line drawn at the top and the bottom of the plate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

USING THIN LAYER CHROMATOGRAPHY

after line drawn

A

a small drop of the mixture is placed on the line at the bottom of the plate and dried using a hairdryer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
USING THIN LAYER CHROMATOGRAPHY | where do you put the plate
the plate was stood in the jar making sure that the spot was above the solvent level
26
USING THIN LAYER CHROMATOGRAPHY | after everything has been set up
the chromatogram was allowed to run until the solvent had risen to the pencil line at the top of the plate
27
USING THIN LAYER CHROMATOGRAPHY | when it has reached the top
plate removed and allowed to dry
28
USING THIN LAYER CHROMATOGRAPHY | why is filter paper placed around the walls of the glass jar
to speed up saturation of the tank with solvent vapour
29
USING THIN LAYER CHROMATOGRAPHY | why are two lines drawn on the TLC plate
one line is needed to indicate where the samples start from, and the other to indicate the distance travelled by the solvent front, which enables the Rf values to be calculated
30
USING THIN LAYER CHROMATOGRAPHY | when is it possible to separate components of a mixture using thin layer chromatography?
when one of the components is attracted to significantly different extents by the stationary phase and/or the mobile phase
31
USING THIN LAYER CHROMATOGRAPHY | when two substances are found to have identical Rf values, what does this mean?
the two substances may be the same, but further evidence is necessary to establish this conclusively
32
2 social and applied aspects of TLC
used in the pharmaceutical industry to determine the purity of drugs used in forensic science to separate colours in dyes extracted from fibres
33
USING COLUMN CHROMATOGRAPHY | stationary phase and where does it go
silica gel, placed in a long glass tube (column)
34
USING COLUMN CHROMATOGRAPHY | what prevents the material from running out
glass wool at the end
35
USING COLUMN CHROMATOGRAPHY | solvent for non-polar substances
ethanol
36
USING COLUMN CHROMATOGRAPHY | solvent for polar substances
water
37
USING COLUMN CHROMATOGRAPHY | how and why is silica kept saturated
kept saturated with the solvent to prevent it from drying out
38
USING COLUMN CHROMATOGRAPHY | where does the mixture go?
added to the top of the column
39
USING COLUMN CHROMATOGRAPHY | how does it separate
the components are adsorbed to a different extent along the column
40
elution
passing solvent through the column
41
eluent
solvent
42
USING COLUMN CHROMATOGRAPHY | first step
the solid phase extraction column was flushed through with methanol using the plunger of the syringe
43
USING COLUMN CHROMATOGRAPHY | second step
the column is then flushed through with water
44
USING COLUMN CHROMATOGRAPHY | what do you do with the mixture
a sample was placed on top of the column to a depth of 1mm
45
USING COLUMN CHROMATOGRAPHY | methanol solution
added to the syringe
46
USING COLUMN CHROMATOGRAPHY | once everything is set up
mixture flows down through column
47
USING COLUMN CHROMATOGRAPHY | separation
separation occurs as the mixture appears as bands of different colours
48
USING COLUMN CHROMATOGRAPHY | final step
different components of the mixture were collected in separate beakers
49
USING COLUMN CHROMATOGRAPHY | when is it possible to separate components of a mixture using column chromatography?
when one of the components is attracted to significantly different extents by the stationary phase and/or the mobile phase
50
USING COLUMN CHROMATOGRAPHY | what is the purpose of the syringe in this experiment?
to allow the solvent to be forced through the column under pressure, thereby achieving a rapid separation
51
USING COLUMN CHROMATOGRAPHY | why is an adapter necessary?
to enable the syringe to be fitted exactly into the column, without this, it is not possible to force the liquid through the column under pressure
52
USING COLUMN CHROMATOGRAPHY | why is it necessary to flush the column with methanol and then water before using it?
methanol will remove any residual organic material from the column, water will then remove any remaining methanol
53
TO SEPARATE A MIXTURE OF INDICATORS USING CHROMATOGRAPHY | why is the gas jar not used for a time after the solvent has been added?
to allow time for the tank to become saturated with solvent vapour
54
TO SEPARATE A MIXTURE OF INDICATORS USING CHROMATOGRAPHY | why are two lines drawn on the paper
one line is needed to indicate where the samples start from, and the other to indicate the distance travelled by the solvent front, which enables the Rf values to be calculated
55
TO SEPARATE A MIXTURE OF INDICATORS USING CHROMATOGRAPHY when 2 substances are found to have 2 different Rf values in an experiment carried out under the same conditions, what does this mean?
the 2 substances are not identical
56
5 instrumental methods of separation and analysis
``` mass spectrometry gas chromatography (GC) high performance liquid chromatography (HPLC) Infra-Red spectrometry (IR) Ultra-violet spectrometry (UV) ```
57
GAS CHROMATOGRAPHY | gas is in
mobile phase
58
GAS CHROMATOGRAPHY | stationary phase
a high boiling point liquid spread on silica gel packed into a long coiled tube of small diameter
59
GAS CHROMATOGRAPHY | where is tube kept
in a temperature controlled oven
60
GAS CHROMATOGRAPHY | where do you put the sample
injected into the column
61
GAS CHROMATOGRAPHY | what is done to the column when sample is in
column is heated to vaporise the sample and it is carried through by a gas such as nitrogen or helium, as these are unreactive gases
62
GAS CHROMATOGRAPHY | separation
the components of this mixture separate out at different rates as they are carried through the column
63
GAS CHROMATOGRAPHY | how results are recorded
as each component leaves the column, a detector records a signal and plots a chart called a gas chromatogram
64
GAS CHROMATOGRAPHY | how do components show up on the chromatogram
as a peak
65
GAS CHROMATOGRAPHY | what is it used for
to measure the level of alcohol in our blood or urine and in drug test samples from athletes
66
HIGH PERFORMANCE LIQUID CHROMATOGRAPHY | function
used to determine non-volatile components of a mixture
67
HIGH PERFORMANCE LIQUID CHROMATOGRAPHY | particles of the solid phase and what can you do
very small, pressure is used to force the mixture through
68
HIGH PERFORMANCE LIQUID CHROMATOGRAPHY | temperature and why
temperature not as high as GC so this prevents the decomposition of substances at high temperatures
69
HIGH PERFORMANCE LIQUID CHROMATOGRAPHY | pressure
the column is not as long and made of material that can withstand the high pressures used
70
HIGH PERFORMANCE LIQUID CHROMATOGRAPHY | where is it used
in food analysis - growth promoters in meat and vitamins in food
71
INFRA-RED SPECTROMETRY | organic compounds
organic compounds absorb infra-red radiation (the bonds do) and the bonds begin to vibrate
72
INFRA-RED SPECTROMETRY | different bonds
different bonds absorb different amounts of energy and so vibrate differently
73
INFRA-RED SPECTROMETRY | finger-print
the vibrations are like a fingerprint for each molecule and the molecules can be identified by checking them against a data-base
74
INFRA-RED SPECTROMETRY | what is it used for
to identify plastics and drugs
75
ULTRA-VIOLET SPECTROMETRY | what may happen when a substance absorbs ultra-violet light
an electron may be promoted o a higher energy level and a spectrum is obtained
76
ULTRA-VIOLET SPECTROMETRY | max absorption
max absorption usually occurs at a certain wavelength, and this helps to identify the compound and its concentration, as absorbance is related to concentration
77
ULTRA-VIOLET SPECTROMETRY | what is it used for?
quantitive determination of organic compounds e.g drug metabolites and plant pigments
78
RECRYSTALLISATION OF BENZOIC ACID AND DETERMINATION OF ITS MELTING POINT principle
more solute is soluble in hot solvent than in cold solvent
79
RECRYSTALLISATION OF BENZOIC ACID AND DETERMINATION OF ITS MELTING POINT first step
5g benzoic acid placed in a beaker and dissolved in a minimum of hot water
80
RECRYSTALLISATION OF BENZOIC ACID AND DETERMINATION OF ITS MELTING POINT why a minimum of hot water
to maximise the yield - benzoic acid does not remain in solution on cooling
81
RECRYSTALLISATION OF BENZOIC ACID AND DETERMINATION OF ITS MELTING POINT first filtration
this hot solution was filtered through a Buchner funnel (under suction, fast), insoluble impurities remain on the filter paper
82
RECRYSTALLISATION OF BENZOIC ACID AND DETERMINATION OF ITS MELTING POINT after first filtration
filtrate was allowed to cool slowly
83
RECRYSTALLISATION OF BENZOIC ACID AND DETERMINATION OF ITS MELTING POINT second filtration
excess solvent filtered off and crystals remain on filter paper and allowed to dry
84
MELTING POINT DETERMINATION | first step
some crystals tapped into the open end of a melting point tube, until 0.5cm full at the end of the tube
85
MELTING POINT DETERMINATION | thermometer
attach tube to thermometer with rubber band
86
MELTING POINT DETERMINATION | prepare boiling tuber
boiling tube half-filled with liquid paraffin and the tube and thermometer were placed in the boiling tube
87
MELTING POINT DETERMINATION | everything is prepared
place boiling tube over bunsen burner and heat, stir liquid paraffin thoroughly throughout
88
MELTING POINT DETERMINATION | find results
the temperature at which the crystals started to melt was noted and recorded
89
MELTING POINT DETERMINATION | after it is done
allow paraffin to cool to 10ºC and repeat with fresh crystals, heat more slowly and record
90
MELTING POINT DETERMINATION | how is melting indicated
by the formation of a visible meniscus
91
MELTING POINT DETERMINATION | if the crystals are pure
a sharp melting point will be recorded
92
MELTING POINT DETERMINATION | if the crystals are impure
a melting point range will be recorded
93
cracking
a process that involves breaking up long chain hydrocarbons for which there is low demand into short chain hydrocarbons for which there is high demand
94
2 types of cracking
catalytic cracking or thermal cracking
95
cracking, for every bond broken
a double bond must be formed in a product molecule
96
if a molecule is cracked in 2 places
there will be 3 products and 2 will have a C=C

Chemistry (Tara) (50 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions