Shangshang Cao essay

Extended Essay
Chemistry
Research Question: How to isolate and
investigate the molecules which provides the
property of erasability to an ink (Pilot
Frixion), as compared to the normal ink
(black ball pen in brand called
“Chenguang”), using column
chromatography and thin lawyer
chromatography?
Name: Cao, Shangshang
Candidate Session Number: 049152-0003
Supervisor: Joy Biswas
School: Nanjing Foreign Language School
Word Count: 4016

Content:
Section number Name of section Page number
I Abstract
II Acknowledgment
III Introduction 1
IV Investigating planning: 2
V Solvent choosing: 3
VI Silica gel chromatography: 6
VII Calculation: 8
VIII Investigate the getting components 10
IX Result and Discussion 12
X Appendix: 14
XI Word Citation 16

Table Content:
Table number Name of table Page number
Table 1 Shows whether there is separation of paper
chromatography in choosing solvent
14
Table 2 Shows whether there is separation of silica
gel plate chromatography in choosing
solvent
15

Figure index
Figure
number
Name of figure Page
number
1.0 The theory of column chromatography 2
2.0 Mix ink with water 3
3.0 Paper chromatography of trial 1, 2, 3 (from left to right) 5
4.0 Paper chromatography of trial 5, 6, 7 (from right to left) 5
5.0 Paper chromatography for non-erasable ink (trial 5) 8
6.0 Silica gel plate chromatography for erasable ink (trail 14) 8
7.0 Column chromatography for non-erasable ink 9
8.0 Column chromatography for erasable 9
9.0 Axis shows outcome of the result of the column
chromatography of non-erasable ink
10
10.0 Two comparative trials after heating 11
11.0 Two comparative trials after wild open 11

I. Abstract:
The following extended essay mainly going to compare the different compounds in
the ink of erasable ball pens and non-erasable ball pens and the properties of those
compounds. This naturally comes up with the research question:
How to isolate and investigate the molecules which provides the property of
erasability to an ink (Pilot Frixion), as compared to the normal ink(black ball pen
in brand called “Chenguang”), using column chromatography and thin lawyer
chromatography?
The reason I chose the concept as my topic is that as a student, erasable pens and
normal ball pens are what I use every day, the effect of an erasable pen as a ball pen is
also what I want to know clearer. Moreover, for the technical approach, chromatography
is what I have learned in previous lessons but only with paper chromatography, which
has already drawn a lot of my interests. Especially for the column chromatography, the
whole process of choosing an appropriate solvent step by step is more a challenge to
me. Getting in touch with more organic solutions will also benefit my future study a lot.
I choose the column chromatography as the main investigation approach to the
whole experiment. The whole experiment can divide into several steps: first, choosing
the solvent for the silica gel chromatography; then, carry on the column
chromatography calculate the Retention factor value compare the two mixture for the
first time; lastly, heat a little bit of the separated layer I got to see whether there is a
change.
From the experiment, I found that heat can actually effect it, that the lower the
temperature of the compounds goes, the more similar the ink of the erasable pen and
non-erasable pen will be. In another word, high temperature will let the erasable ink
disappear.
Word count: 295

II. Acknowledgment：
I want to give thanks to all the people who have helped me both directly and
indirectly. A special thank for my teacher, Mr. Joy Biswas, who help me a lot since the
beginning of the extended essay on deciding the topic and emphasized point. In the
following experiment, Mr. Biswas told me many practical tips of running an experiment
since most of the information about column chromatography I got from the internet is
not that accurate. All the tips help me carry on my experiment fluently.
Really thanks to Mr. Chen, the technician in our school’s chemistry lab, who helped
me a lot in finding some rare solutions that I needed and ordered a lot of equipment
necessary for experiment for me. Also other technicians including Ms. Zhou and Ms.
Hua also supported me a lot that allowed me to stay in the chemical lab until around
six, so that I could have a long period of time continued my experiment.
Thanks to all my friends for bearing the stimulating smell of my clothes because of
the organic solution.

1
III.Introduction:
"Pilot Frixion" is a kind of pen that became popular recently among students. It can
not only be used as a normal black ink pen on paper, but also be erased from the paper
by normal erasers just like a pencil. It is useful for us to correct our mistakes without
making the paper work untidy. After using it in person, I found that the words wrote in
the erasable pen would be gradually disappeared after two or three years, while the
words wrote in normal pens seldom have changed. Logically speaking, there must be
some specific compounds that make the ink from non-erasable to erasable, since the
erasable pen could be also used as a normal pen, showing the blank color, and all the
protection method for both pens are the same, so I am going to investigate the property
of the unknown particles which let the ink become erasable. Naturally, I come up with
my research question:
erasability to an ink (Pilot Frixion), as compared to the normal ink(black ball pen
chromatography?
My hypothesis is that the ink of the erasable pen might be influenced by the change
of temperature, and get in touch with air (or be more specifically, the oxygen and
hydrogen in the air), because I usually see the words I wrote at the first class with
erasable pen become lighter during finals. I found words even almost disappear after
three years when I pack up the homework and papers than I have done for the whole
middle school. There is no evident difference in the condition I stored those papers,
apart from the temperature which I cannot control as the season goes, and also how
those papers get in touch with air. The hypothesis also make sense to me during the
process we actually want to erase the words. Logically thinking, there is no obvious
changes of condition of the ink and the surrounding during the process of erasing. The
only thing I could think about is the heat come from the friction between erasers and
papers. Although the heat feels nothing to me, but it might mean a lot to those special
compound. That may also explain why when we used the erasable ball pen, we need to

2
spend extra strength to erase the words than to erase the words in pencils. This
investigation may relate to the unit learned about the bonding.
I choose to use the column chromatography to be my main experimental method,
because column chromatography is a really good technique for separating and
identifying the components of a mixture by their chemical properties (Brown, C.), so
that I can broadly separate the substances in two kinds of ink to see the differences.
IV.Investigating planning:
As mentioned before, I choose to use column chromatography to separate the
molecules in ink. There are many kinds of chromatography, like thin layer
chromatography, paper chromatography, column chromatography and ultraviolet high
performance layer chromatography. After reading the feature of these. I think column
chromatography is better than other kinds of chromatography because it can use both
in separating and analyzing the inks. The column includes a stationary phase (mainly
use a solid, or a liquid has a solid stand at the back) and a mobile phase (usually use a
liquid). The column chromatography carries on when the liquid solvent passes
through the stationary phase, which usually contains in a glass or plastic container.
Because of the different properties of the different components in the mixture, these
components will stick on the surface of the absorbent (the stationary phase) in
different levels.
Although the
compounds are too
small to be
observed, once an
abundant of
compounds stick
together it can
make clear
separated layers
Figure 1: the theory of column chromatography

3
from out looks of the column. Then, I can get the different layers of components when
we let the liquid keep dropping down to the beaker with different lawyers.
After deciding use which specific kind of chromatography, I need to determine the
substance for the stationary phase and a mobile phase. About the stationary phase, there
are several kinds that are commonly used, such as silica gel, alumina and molecular
sieve. The different sizes of the molecules of the stationary phase greatly determine the
effect of the stationary phase------ the larger the molecules are, the more effective this
stationary will be for the gravity chromatography; the smaller the molecules are, the
more effective this stationary will be for flash chromatography. Considering the
complex components of the ink, I chose silica gel chromatography for my experiment.
For solvent, I will choose based on the polarity. In order to understand and experience
the column chromatography more comprehensively, I am going to choose or even make
my own solvent for my experiment. Just to save time, I choose to use paper
chromatography at first stage to help me choose the suitable solutions to combine for
the final solvent. Then, run the thin layer chromatography using the silica gel plate
when the solution choosing preciously to adjust the ratio among each other. Then after
the solvent has been choosing, I am going to start formal column chromatography, in
order to generally separate the ink by molecules property, so that I could further
distinguish the main difference between two inks.
V. Solvent choosing:
Before start everything, since all these choice will depends on the polarity of the ink
(the inks of the normal roller ball
pens and Pilot Frixion) I used, I just
simply mix both inks with distilled
water, to see whether they can
dissolve in water. The result shows
that the non-erasable ink can be
mostly dissolved in water and the
Figure 2: mix ink with water

4
clear colorless water turned to black liquid. At the same time, the erasable ink can be
practically dissolve in water, with several black soft floccule, and the clear colorless
water also turned to black. Consequently, I know that both inks are somehow polar.
(Figure 2). The polarity of the solvent should be similar to the polarity of the ink.
Every solute has a specific polarity, even for different concentrations of the same
solvent. The ideal solvent can separate the sample test material into different
components in separate concentrated zones with certain distance that can let observer
clearly distinguish. In order to find the solution made up of my ideal solvent, I chose to
run paper chromatography firstly to see how each solvent works when separate the
sample liquid. During this first step of experiment I need to follow the rule of a paper
chromatography, including the paper does not touch the sides of the beaker; the original
level of the solvent should not over the pencil line; first put solvent and then put the
paper with solvent. After reading materials, I chose several organic solution, including
the extreme polar, the extreme non-polar and relatively neutral one.
At first several trails, there is not any separation exist. I think about whether there
is a systemic error or not. Then I thought it might be the amount of the sample I used.
Preciously, when I done the thin lawyer chromatography, I only need one drop from
pipette of the sample to make sure the separation is clearly enough in a controllable
pace. However, my pen ink may not really an evenly proper solution, so I need to put
more than one drop of the ink in every spot so that I can make sure that this spot contains
all compounds in the mixture. At the same time, I need to make sure that the ink is dry
before I carry on paper chromatography.
Since most of the solvent I choose is organic solutions and will easily
evaporate, in order to make sure the solvent touch the paper has the ratio I suppose, I
put a petri dish on each beaker as a cap.
After all trials I collect my data in a table, which shows in the appendix of table 1.
According to the table, the outcome column, “yes” or “no” means whether the
sample ink has been separated or not. Overall, I get two kinds of separation, one is in

5
spots and one is in line. The percentage on for the outcome column shows how far did
the separation goes of the paper, because for paper chromatography, the only direct way
for me to distinguish whether the separation are caused by the same substance is by the
distance it goes for the pencil line.
Form the data I get from paper chromatography. I know that Hexane didn’t help me
with my chromatography. One the other hand, distilled water, CH3COOH, n-Butanol,
ethanol and ammonia may all help with my solvent，especially the element Nitrogen.
The combination of solution shown in trial 5 and 3 may be the good foundation of my
solvent in silica gel chromatography. (Shown in figure 3, 4)
By a step further, I chose to carry on more trials on the silica gel plate. The results
show in appendix of table 2.
For the trial 11, 12, 13, the main purpose of those is to make sure that the elements
nitrogen is important to the component of the solvents, so involving a new solution
C3H2N2. Originally, I was planned to use CH3CN, however, our school cannot access to
Figure 4: Paper chromatography of trial 5, 6, 7 (from right to left)
Figure 3: Paper chromatography of trial 1, 2, 3 (from left to right)

6
this solution, so I choose to use C3H2N2 as a replacement. Firstly, I use ethanol together
with C3H2N2. In the trial 11, there is separation but not very clearly, so I try to get more
clear separation by change the ratio between C3H2N2 and ethanol. However, in trial 12
and 13 don’t show any separation at all. This is also a problem that I cannot understand.
Then, I try to keep the ratio of C3H2N2 and ethanol is one to one in all solvents. At the
same time, add n-Butanol, acetic acid, C6H12 and C9H14O6 to change the polarity of
the solvent to find the best ratio for the separation.
For the trial 20, 21, 22, I mainly try to find out whether the oil (petrol) could be a
part of a solvent, since its polarity is a greatly extreme compared to the distilled water.
However, the three trails don’t really give me whatever the result I expect. The main
reason I suppose is that no matter how much other solution I add to the petrol, the highly
stickiness of the petrol cannot be avoid, so the solvent cannot “climb” up along the plate.
So petrol is not a good solution of for the final solvent.
With all the trials above, I choose to use the trial 14 as the basic solvent for the
separation of the erasable ink, and the trial 5 and 11 for the models of the solvent of the
separation of the non-erasable ink.
VI. Silica gel chromatography:
After ready for the solvent, I get prepared for the silica gel column chromatography.
First of all, need to decide to the amount of silica powdered I need to use. The amount
of silica powder used directly related to the length of the chromatography. In the
previous paper chromatography and silica powdered plate chromatography, I could only
see clearly two separations at most for different inks, so I expect to see two layers in
silica gel chromatography. Also, basing on the rule of saving the chemical resource, and
the limitation of the length of the column, I first choose to use 20g of the silica gel
powdered.
During the setting of silica gel chromatography, there are many things might
influence the final result that I need to pay attention. First of all, there need to be no

7
bubble holes throughout the column, because the gas contain in the bubble holes might
also be part of the separation. Also, not matter it is pulling sand or ink, both should be
slowing in steps so that it won’t destroy the originally stable lawyers. In the first attempt
of the silica gel chromatography. I see two layers in light yellow. It is too faint that I
even cannot make sure whether it is really exist or it is because of my eyesight. So I
borrowed the ultra-violet lamp from the lab. Under the UV light, the two layer shows
clearer. In order to see the boundaries of the lawyer more clearly, I run the silica gel
chromatography again with more ink each trail. For the erasable ink, I got one clear
separation in lawyer, and a blurred lawyer. For the non-erasable ink, I surprisingly got
may be three lawyer. But then the problem came, especially, for my experiment, it is
hard to judge whether the third lawyer is really a new lawyer of separation or it is just
again the first lawyer, due to the length of the burette.
Although I cannot be sure about each of the components, but there is one thing that
I can notice from the column chromatography is that the original solvent is a little
yellow but once the solvent comes out again with the ink, the color darken in different
degree to the brownish yellow. On the other hand, the solvent of the erasable ink is
originally colorless, and it is still colorless.
As a result, I decided to do the silica gel column chromatography again by
enhancing the length of the silica gel column chromatography into using 40g of silica
powdered. However, there is not any separation in both trails at all, with the exactly
same solvent as the first trials. Which tells me that there are systemic errors in both
column chromatography experiments. I think the result might because the original
solution C3H2N2 I use is kind of solution with high viscosity, having a melting point at
around 32.2 degree Celsius, and to run through a full trial of column chromatography
with longer burette needs to take over one hours, so at the end of the column
chromatography the silica gel might become very close to the state of the solid which
let the substance layers not able to be going down or stick on the silica gel properly.
Due to the limitation of the experimental condition, I am not able to carry on the
experiment in a warmer condition, also including the problems of the solvent. For one

8
trial of silica gel the column chromatography I left the column of silica gel and solvent
overnight. Then in the next day, this column gives me no separation in inks at all. Which
also lets me aware that the physical property of the solvent might also affect the result
of silica gel chromatography.
Another obvious difference between the first two column chromatography and
these two is that, both the outcomes of the erasable ink and non-erasable ink are become
more yellowish in color. I think it may be a sign of the effect of the temperature, which
fit my hypothesis.
VII. Calculation:
After carry on all trials of column chromatography, I need to then calculate out the
Retention factor value, known as Rf value, is defined as the distance traveled by a given
component divided by the distance traveled by the solvent front. For a given system at
a known temperature, it is a characteristic of the component and can be used to identify
components (Oxford). In my extended essay experiment, I could use the data from value.
Firstly, about the silica powered plate, I choose to use the result I got from trial 5 and
14 with clear separation in dots. (Figure 5, 6)
Figure 5: paper chromatography
for non-erasable ink (trial 5)
Figure 6: silica gel plate
chromatography for erasable ink
(trail 14)

9
In figure 5, the length of the solvent goes from the pencil boundary is 6.5 centimeter；
the length measured from the center of dots to the pencil boundary, which, in this case,
is about 1.6 centimeter. So the Rf value here is about 16/65 ≈ 0.188. In figure 6, the
solvent goes about (6.4 -1.5) = 4.9 centimeter and the spot stop at 0.3 centimeter, so the
Rf value is 3/49 ≈ 0.061. And the route of the ink goes about 1.5 centimeters, which is
15/49 ≈ 0.306.
On the other hand about the data get from the silica gel chromatography, is relatively
unsure. Different form the plate, because column has thick lawyers, I need to take
approximate mid-point of each lawyer to calculate the distance. Because the column is
a three-dimensional object, I cannot make sure the distance of the solvent goes, but I
can approximate estimate the value from the column of the solvent that comes out. The
column shown below:
Figure 8: Column chromatography for erasable inkFigure 7: Column chromatography for
non-erasable ink

10
For the non-erasable ball pen, when the first lawyer completely comes out from the
column, there are 16 ml solution comes out. When the second lawyer completely comes
out, there are another 10 ml solution comes out. When the third lawyer comes out, there
are another 19 ml solution comes out. And when the column totally finished the rest of
the 6 ml solution comes out. To have a better view of the ratio of each of the lawyers to
the rest of the solution, I choose to represent the lawyers in a two dimension axis which
shows below, the numbers on the axis are getting form the accumulated number, which
means each term is the sum of all the previous terms.
So the Retention factor value for the first lawyer is 16/51 ≈ 0.314; for the second
lawyer is 26/51 ≈ 0.510; for the third lawyer is 45/51 ≈ 0.882.
For the erasable ball pen, for the same logic, when the only lawyer comes out it
is about 14 ml. When the column chromatography comes out, there are another 37 ml
solution come out. So the Retention factor value is 14/37 ≈ 0.37
Comparing the value of the thin lawyer chromatography with is the one get in
column chromatography. I found that the later data are commonly greater than the
former one. This might be explained by that there are many solvent still remain in the
column together with the silica gel.
VIII. Investigate the getting components:
As noticed before, there is a clear color difference between the result get in the
column chromatography of erasable ink and non-erasable ink, and between the result
get in both column chromatography in different temperature. So I was thinking whether
I can be more clearly about the factor that influence the effect of the erasable pen as a
Figure 9: Axis shows outcome of the result of the column chromatography of non-erasable ink

11
normal pen. At this point, I got three beakers with the solvents and different components
of the non-erasable ink. One the other hand, I take one beaker with one lawyer of the
erasable ink. In total four beakers. I choose to set up two comparative trials. In first
trials, I took a little bit of the solutions from four beakers and leave it wide open for 4
hours. In the second trials, I took a little bit of the solutions from four breakers, made
them all in a water bath at about 32 degree Celsius, in two minutes.
After two minutes, two of the solutions that have a lighter yellowish color
compared to itself before the water bath. And the one of the erasable ink solution almost
become colorless again. (Figure 10)
After four hours, for the four beakers that are wide open, the only have a
decrease in volume, which might cause by the evaporation of the organic solutions that
are in the original solvent. For the color, there is not obvious difference occurring.
(Figure 11)
So from these two comparative trials I found that the greater temperature is what
influence greater than the surrounding that get in touch with the air.
Figure 10: Two comparative trials after heating Figure 11: Two comparative trials after wild open

12
IX.Result and Discussion
From the column chromatography, I found that there are at least three groups of
components that the non-erasable ink and erasable ink differ from. Form the real life
situation. I can know that since the polarity of the non-erasable ink is much higher than
the erasable ink, once there is water spilling out on a written work. The work with non-
erasable ink will be contaminated faster and wider than the work with erasable ink.
Also, from the last two comparative trials, I can draw the conclusion that the
erasable ink will be almost “disappear” is greatly possibly caused by the higher
temperature. That may also explain that why the words on work with erasable ink
collected both in totally closed box or just placed disordered will all be disappear, or
become lighter over the summer, compared to the wide opened words written in the
normal black ball pen.
In fact my result is just a very ambiguous outcome. The result I got cannot be very
comprehensive and accurate. The whole experiment could be improved in following
parts:
First of all, because of the limitation of time and the variety kinds of solutions I can
get through the school chemistry laboratory, I cannot really find the most suitable
solvent for the ball pen ink. And because this is the first time that I try to struggle with
different ratios of different solutions, lack of experience made me waste a lot time in
those trials that will obviously not given the answer I want. That is why in table 1 and
table 2, most of the trials gives no separation in the outcomes section.
In addition, I am aware of a systematic error that the paper I used in this paper
chromatography is too short. Since the ink is a really complex mixture. Some of the
solvent may show its separation when the paper gets longer. Or some of the solution
can actually separate more than one portion of the ink but under the limitation of the
length, it only shows one or even nothing. The distance of the separation may also be
more accurate.

13
Secondly, I choose the C3H2N2 for my solvent in the end which with the best
outcomes of a separation in chromatography. But since its physical properties of high
melting point, the silica gel chromatography did not run as well as I supposed in the
second set.
For chromatography, solvent is the most essential thing throughout. As a result,
during the stage of choosing the solvent, it is better to try as much solutions as possible
in different ratios, to find the best one. As a proper solvent, not only should focus on
the effect of separation but also whether the physical property is suitable for the
chromatography. Moreover, for the solvent, the ratio is very important. So for each steps
of measuring the solution, there much be not zero error, parallel error, and try to make
sure that all the solution in the cylinder goes to the beaker.
Further speaking, there are many more methods like UV visible spectrum, High
Performance Layer Chromatography, and Nuclear Magnetic Resonance Spectroscopy
also could help in further investigation. However, every method has both advantages
and disadvantage. For example, all approaches mentioned above involved high cost.
For Nuclear Magnetic Resonance Spectroscopy, it can accurately separate each
compound, but mostly one kind each time.
Finally, to answer my research question:
erasability to an ink (Pilot Frixion), as compared to the normal ink (black ball pen
chromatography?
As I supposed, the increase in the temperature of the surrounding and getting in
touch with the air slightly change the compound which provides the property of
erasability to an ink. This cause the “disappearance” of the words.

14
X. Appendix:
Table 1: Result for paper chromatography in choosing solvent
Solution used to make solvent and its ratio
Outcome
(separated or not)
No.
of
trial
H2O
CH3COOH
1.0M
CH3COOH
2.0M
Hexane
C6H14
n-Butanol
CH3(CH2)2C
H2OH
ETHANOL
C2H6O
Ammo
nia
NH3
Non erasable
ink
Erasable
ink
1 1 1 line for 90% No
2 6 3 1 line for 40% No
3 4 2 2 line for 60% No
4 1 No No
5 5 3 12
spot at 20%
with dots
No
6 3 6 12 No No
7 1 line for 90% No
9 2 3 5 No No
1
0

15
Table 2: Result for silica gel plate chromatography in choosing solvent
Solution used to make solvent and its ratio
Outcome
(Separated or not)
Number
of trial
H2O
acetic acid
CH3COOH
acetone
CH3COCH
n-Butanol
CH3(CH2)2CH2
OH
Ethanol
C2H6O
ammonia
NH3
C3H2N2 CHCl3 C6H12 C9H14O6 C8H8O2 Petrol
Non-
erasable ink
Erasable
ink
12 2 1 No No
13 1 2 No No
14 1 3 2 2 No
line for
40% , dots
15 2 2 1 2 line for 20% No
16 1 1 2 No No
17 1 1 2 No No
18 1 1 1 2 No No
19 1 2 1 1 No No
20 1 1 1 No No
21 1 1 1 1 No No
22 1 1 1 1 No No

16
XI.Citation:
1. Vogel, A., Furniss, B., Hannaford, A., SMITH, P. and TATCHELL, A. (1989).
Vogel's textbook of practical organic chemistry. 5th ed. Harlow: Longman.
2. Brown, C. (2009). Higher level Chemistry. PEARSON BACCALAUREATE
higher level Chemistry developed specifically for the IB diploma
3. Dict,youdao,
http://dict.youdao.com/ugc/view/q?url=http%3A%2F%2Foimagec1.ydstatic.com%2
Fimage%3Furl%3Dhttp%3A%2F%2Fbricker.tcnj.edu%2Ftech%2FF06-
09.jpg%26product%3DPICDICT , access data: November. 9th.2014
4. The Ministry of health of the people's Republic of China. The drug standard
[S]. two (fourth volumes), 1995.105107
5. Anon, (2014). [online] Available at:
http://www.erowid.org/achive/rhodium/chemistry/equipment [Accessed 27 Sept.
2014].
6. SEEP CHEMISTRY, (2014). CHEMISTRY LESSON PLAN. [online]
Available at: http://.www.shodor.org/ssep/lessons/ink.html[Accessed 15 May 2014].
7. Mifsud, S. (2014). MarZ Kreations Web Site - Directory browsing Denied
[MarZ Chemistry]. [online] Marz-kreations.com. Available at: http://www.marz-
kreations.com/Chemistry/Chromatography [Accessed 15 May 2014].
8. Saferstein, R. (2007). Basic laboratory exercises for forensic science. Upper
Saddle River, N.J.: Person/Prentice Hall.
9. Belgacem, M., Blayo, A. and Gandini, A. (1996). Surface characterization of
polysaccharides, lignins, printing ink pigments, and ink fillers by inverse gas
chromatography. Journal of Colloid and Interface Science, 182(2), pp.431--436.

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