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CHEM 219 Lab Exams 5-8 | Questions and Answers | 2025 Update | 100% Correct - Portage.

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CHEM 219 Lab Exams 5-8 | Questions and Answers | 2025 Update | 100% Correct - Portage.

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i Question 1 Not yet graded / 10 pts



( 1) Name the two major classes of pigment molecules being isolated and separated in the column chromatography experiment. (5
points)


2) Which of the two classes of pigment is POLAR? (5 points)


Your Answer:

1) Chlorophylls and carotenoid

2) Chlorophylls are more polar due to heteroatoms




Answer:

1) Chlorophylls and carotenoids (carotenes).

2) The chlorophylls are more polar.




Not yet graded / 10 pts
Question 2


Which was
The organic solvents poured into the column flowed through a white powder known as alumina (AIZC@) - aluminum oxide.
the stationary phase, and which was the mobile phase? Explain.


Your Answer:
collected at the top of the alumina
The stationary phase is a fixed phase. this occured when the sample was running into sand layer, it
as a concentrated green band. We used hexane to fill column. We saw the initial phases of separation before
stationary phase bed

, /7 Question 2 Not yet graded / 10 pts



The organic solvents poured into the column flowed through a white powder known as alumina (Al,O3) - aluminum oxide. Which was
the stationary phase, and which was the mobile phase? Explain.


Your Answer:

The stationary phase is a fixed phase. this occured when the sample was running into sand layer, it collected at the top of the alumina
stationary phase bed as a concentrated green band. We used hexane to fill column. We saw the initial phases of separation before
adding hexane and stopped this when we eluded the caratine.

The mobile phase is where movement of the band occured the first mixture used was 70% hexane 30% acetone and this process was
sped up with 20% ethonol, 80% acetone - here we saw the green band moving. This phase brought out the chlorphyls.



fi"
|
| Alumina is the STATIONARY PHASE in the separation - it does not move during the separation, the components of the sample
[ pass through it. The organic solvents are the MOBILE PHASE in the separation - the solvents move, pulling the components of
!
l the sample along with them.




Not yet graded / 10 ptsj
F Question 3


In the initial preparation of the spinach sample, from spinach leaves, what two compounds was the spinach ground with and what was
the purpose of each?


Your Answer:

The spinach was ground with sodium sulfate powder which acted as a drying agent to pull the moisture out of the leaves and sand
which acted as a maserating agent - it helped to grind up the spinach and break open the cells to release pigments.



I v
‘1
| |
;J Sodium sulfate (as a drying agent) and sand as a macerating (grinding) agent. ’l

| paese)
¥ 3ol ASPs i . Ry R izP S Re s o
N R o N e R N N S Y 1O




EXAM 6

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Subido en
30 de agosto de 2025
Número de páginas
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Escrito en
2025/2026
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