Student’s Name
Student’s Lab Partner
Mods
Empirical Formula of an Oxide of Tin
Purpose:
Within completing this lab, it was intended for the experimenter (student) to determine
the empirical formula of an oxide of Tin by means of experimenting. This goal would be
accomplished by finding the masses of the various substances experimented with, which
30 mesh tin, Tin Oxide, and Oxygen. These various measurements would then be used to
determine the empirical formula of the Tin Oxide produced within the experiment.
Data:
Mass
Object/Substance
Mass (g)
1 dry 200 mL clean glass beaker
83.954
1 dry 200 ml clean glass beaker with about
2g (2.011g) of 30 mesh tin
85.965
1 dry 200 ml clean glass beaker with Tin
Oxide after 5 heatings and 1 cooling (10
minutes at setting 2, 3 minutes at setting 4,
3 minutes at setting 6, 10 minutes at setting
8, about 10 minutes in a ceramic oven, and
1 overnight cooling)
86.723
Observations Before, During, and After Heatings
Heating
Number
0
(Combining
nitric acid
with 2g of
30 mesh
tin)
1
Heat
Plate
Setting
Amount
of Time
(Minutes)
Before,
During,
or After
Heatings
0
About 8
Before
2
10
During
Observations
When the nitric acid was added to the
glass beaker filled with 2g of 30 mesh
Tin, the mixture turned a gray, light
brown color with a smooth appearance.
In addition, the substance began to
bubble, which then sped up after
approximately 3 minutes and a brown
gas was released. After about 4 minutes
and 30 seconds, the mixture changed
from being gray, light brown in color, to
a creamy, gray, yellow, brown color.
The smooth appearance remained within
the mixture. At this point, it seemed as
though the largest amount of the brown
NO2 gas was released. In addition,
condensation began to form on the sides
of the beaker. After approximately 8
minutes, the mixture changed to a
slightly off white, light gray color that
contained a few “specks” of a silver,
gray substance. But, the substance
remained its smooth texture. Also, the
brown gas ceased to be produced from
the mixture, and the bubbles had
stopped forming and or popping.
The slightly off white, light gray
mixture with the gray “specks” had the
appearance of having its contents
separated. A separation between the
speckled light gray, white mixture and a
watery milk looking mixture could be
seen after approximately 5 minutes
within the experiment. After the 10
minutes of heating were completed, 3
layers could be seen within the mixture.
All three of these layers had a smooth
appearance as before. There was a thin
very light white, almost clear top, a light
milky white middle, and a white, gray
speckled bottom. In addition, the top
2
4
3
During
3
6
3
During
4
8
10
During
layer contained many small bubbles.
During this heating, larger bubbles
began to form within the mixture and
the mixture seemed as if it were at an
almost boiling simmer. At this point, the
3 layers formed two layers once again
and included a watery milky white top
and a speckled bottom. Large bubbles
remained within the top layer of this
mixture after the heating. Other than
these bubbles, the mixture had the
appearance of being very smooth.
Many of the gray speckles that were
held within the bottom layer of the
mixture began to rise up through the
mixture and formed bubbles that then
popped. During this heating, the mixture
came to a rolling boil that was a creamy
white color with a smooth texture. Very
large bubbles formed and popped within
the middle of this heating. After the
heating, a large amount of the substance
had been splattered onto the sides of the
beaker as a result of the numerous
bubbles popping and the rolling boil.
The rolling boil and large bubbles
forming and popping continued after
this heating.
After only a minute or two, the mixture
within the beaker began to make loud
popping noises and began to release a
large amount of a white, clear, cloud
like gas. In addition, a lot of the
substance began to not only splatter onto
the sides of the beaker, but also to
splatter outside of the beaker onto the
table, hood, and heating apparatus. The
mixture within the beaker had a very
dry, rough, powdery look to it and was a
off-white, gray color. Toward the
middle of this heating, the bubbles
began to slow, the popping noises
stopped, but the gas continued to be
released. The mixture within the beaker
soon had a light yellow tint to it and the
appearance of being more dry and
5
(Cooling
overnight
after 5
heatings)
Ceramic
Oven
(Not
heated)
About 10
During
Overnight
After
powdery. With about 3 minutes left
within the heating, the gas soon slowed
and became more clear rather than the
whitish gas that had been released
previously. In addition, a small amount
of the substance that had been splattered
onto the sides of the beaker had fallen
off the sides and landed within the main
bottom part of the beaker. The substance
that fell to the bottom of the beaker had
a very dry, off-white, gray appearance.
(Done by Mrs. Marks)
The Tin Oxide that had previously been
“splattered” onto the sides of the beaker
had fallen off of the sides and was then
deposited into the bottom main part of
the beaker. In addition, a rough, off
white, beige, residue remained on the
sides of the beaker where the Tin Oxide
had previously been located. The main
bottom part of the beaker was filled with
large pieces of Tin Oxide with a small
amount of Tin Oxide that was smaller
than sugar granules but larger than
powder. Also, some of the small
granule-like pieces of Tin Oxide were a
pale, dull, light, yellow color while a
majority of it remained the dull, gray,
off white color. These pieces were also
very course. The larger pieces of the
resulting Tin Oxide were slightly curled
at the edges and had the appearance of
having many cracks on the surface. The
edges appeared to be rough, while the
surfaces of the pieces were smooth and
covered with cracks. In addition, some
of these larger pieces had the dull, gray,
off white color on one side and the pale,
dull, light yellow color on the other.
Both of these sides appeared to be
curled and rough on the edges, and
smooth with many cracks on the
surfaces. Also, the bottom of the beaker
had cracked.
Calculations:
Mass of Tin used:
Mass of the beaker with 30 mesh Tin– Mass of the beaker
85.965g – 83.954g
2.011g of Tin used
Mass of Tin Oxide formed:
Mass of the beaker with Tin Oxide (beaker after 5 heatings) – Mass of the empty beaker
86.723g – 86.954g
2.769g of Tin Oxide
Mass of Oxygen used:
Final mass of Tin Oxide – initial mass of tin
2.769g – 2.011g
0.758g of Oxygen used within the final product
Moles of Tin in the final product:
Mass of the final product – mass of the Oxygen used within the final product
2.769g – 0.758g
2.011g of Tin within the final product
g of Tin* 1 mol of Tin/ the number of grams that equal1 mole of tin
2.011g of Tin* 1 mol of Tin/ 118.71g of tin
0.01694 mol of tin
Moles of Oxygen within the final product:
Final mass of Tin Oxide – the initial mass of Tin Oxide
2.769g – 2.011g
0.758g of Oxygen within the final product
g of Oxygen within the final product * 1 mol of Oxygen / the number of grams that equal
1 mol of Oxygen
0.758g of Oxygen * 1 mol of Oxygen / 16.00g of Oxygen
0.0474 mol of Oxygen
The exact ratio of mole of Tin to moles of Oxygen:
Moles of Tin: moles of Oxygen
0.01694 mol of Tin: 0.0474 mol of Oxygen
The whole number ratio of moles Tin: moles of Oxygen
(moles of tin) Moles of Tin: moles of Oxygen (moles of tin)
0.01694 mol of Tin/ 0.01694: 0.0474 mol of Oxygen / 0.01694
1 mol of Tin: 2.80 mol of Oxygen
1 mol of Tin: 2.80 mol of Oxygen
(Round to whole number) 1 mol of Tin : 2.80 mol of Oxygen (Round to whole number)
1 mol Tin: 3 mol Oxygen
Questions:
1. What is the empirical formula of the oxide of Tin synthesized in this procedure?
The empirical formula of the oxide of Tin synthesized within this procedure is SnO3.
2. What is the name of this Tin Oxide?
The name of the Tin Oxide produced within my experiment is Tin (VI) Oxide.
3. There are 2 known oxides of tin. Write the formulas and names of these 2 oxides.
A known oxide of Tin is Stannic Oxide [Tin (IV) Oxide] which has the formula SnO2.
The other known oxide of Tin is Stannous Oxide [Tin (II) Oxide] which has the formula
SnO.
4. How would your results for the exact ratio differ if the sample was not completely dry
before determining the mass? Explain.
If the sample was not completely dry before determining the mass of the Tin Oxide, then
the mass of the sample would be higher than it was supposed to be. This would in turn
cause the appearance of the Oxygen having a greater mass thus causing the exact ratio to
differ by having the Oxygen’s mass augmented from its true form. This would occur due
to the sample including other substances, such as water (H2O) that would add their
masses to the total mass of the Tin Oxide when measuring. If the total mass of the Tin
Oxide were to be higher that it actually was due to the water adding its mass to the mass
of the Tin Oxide, then the Oxygen would appear to have a higher mass that it actually had
due to the added mass of the water. In turn, this would affect the exact ratio of the
components within the sample by having the Oxygen to have an incorrect calculated
mass, due to the water’s added mass, thus creating an incorrect ratio between the Tin and
the Oxygen.
Conclusion:
Within the scope of this experiment, the empirical formula of the Tin Oxide
created was found to be SnO3. By calculating the empirical formula by means of creating
the Tin Oxide and calculating the masses of the Tin and Oxygen within the resulting Tin
Oxide, I have learned many things. First, I have learned that because you are not able to
measure all things directly, such as the mass of the Oxygen within the Tin Oxide, that
you are still able to calculate the mass by using simple calculations such as subtracting
the mass of the Tin Oxide by the mass of the initial Tin used. Also, I have learned what
scientists must do in order to calculate the empirical and chemical formulas of substances
from first creating the substance to actually calculating the formula. And finally, I have
learned that many factors within the experiment may not always be able to be controlled,
thus always allowing some sort of error to occur. Through this experiment, it was
determined that the Tin Oxide produced had the empirical formula of SnO3.
Within this experiment numerous errors occurred that could not be controlled,
thus resulting in inaccurate data when calculating the empirical formula of the Tin Oxide
after the experiment. Some of these errors include a large amount of the Tin Oxide
“splattering” out of the beaker thus landing onto the heating apparatus, hood, and tables,
the Oxygen’s mass being in accurate due to it not actually being measured, and some of
the Tin not fully reacting with the Nitric Acid. When the some of the Tin Oxide
“splattered” out of the beaker and onto the objects surrounding it, this caused the mass of
the Tin Oxide produced to become decreased by not including the mass of the Tin Oxide
outside of the beaker after the heatings. This in turn would have created an inaccurate
mass of the Tin Oxide produced due to a large portion of the Tin Oxide produced not
being included within the final mass of the beaker and Tin Oxide after the heatings. This
in turn would have led to inaccurate calculations when finding the amount of Oxygen
used to produced the Tin Oxide.
In addition, because the mass of the Oxygen within the Tin Oxide could not be
directly measured, the mass may be inaccurate. This inability to directly measure the
mass of the Oxygen within the Tin Oxide allows errors in the measurement to be present.
Also, the measurement of the amount of Oxygen used to produce the Tin Oxide would
have an inaccuracy to it due to the possibility of the Tin Oxide produced containing
various substances such as water, if the Tin Oxide were to not be fully dry when finding
the mass of the Tin Oxide, or NO2, if the brown gas were to not have been completely
evaporated before beginning the heatings. Having these substances within the resulting
Tin Oxide when finding the mass of the beaker and Tin Oxide would result in inaccurate
results when calculating the amount of Oxygen used to produce the Tin Oxide due to
them adding their mass to the calculated mass of Oxygen.
Also, if the Tin were to not have fully reacted with the Nitric acid, this would
have also caused some inaccuracy within the results due to the Tin Oxide produced
containing other substances, thus not being pure Tin Oxide. Due to some of the Tin
Oxide produced within my experiment having the appearance of being a dull, light, pale,
yellow color, I can infer that the Tin Oxide produced contained some other substances
and was not pure Tin Oxide. Due to this, it can be inferred that the Tin Oxide produced
may have had some other substances held within, and was not pure Tin Oxide, thus
causing the calculated mass of the Oxygen held within the Tin Oxide to be higher than it
actually was. Overall, these inevitable errors would have caused some degree of
inaccuracy within my results when calculating the empirical formula of the Tin Oxide
produced within the experiment.