The lab is called the CSI lab. The purpose of the lab
is to show physical and chemical properties of different
substances and to show just because two substances look alike
does not mean they have the same chemical properties.
The materials are indicator solution, a glass rod, a
test tube, Bunsen burner, test tube tongs, paper, wood splint, a
beaker, acid solution, a wash bottle, and the 5 unknown
chemicals. First off for "Test A" you place a small measurement
of substance on a clean piece of filter paper, then inspect with
glass rod. Second for "Test B" fill a beaker with water, add a
small amount of substance, stir, observe, and then add 3 drops of
indicator solution to your beaker. For "Test C" you put a small
amount of the unknown chemical in a test tube and "melt" the
chemical. For "Test D" you place substance on a wet wood splint
and swab it into the flame. Last of all for "Test E" you place a
small amount of the substance into a beaker and using a wash
bottle squirt enough acid solution over the substance to cover
For "Test A" all the samples except 4 were white fine
powder, and sample 4 was white crystals. For "Test B" samples
control, 2, 3, and 4 dissolved, but samples 1 and 5 did not.
During "Test C" samples 1 and 4 did not burn, samples control and
3 had moisture on the mouth of the test tubes, and samples 2 and
5 smoked a bit but only 2 burned. For "Test D" samples control,
1, 3, and 4 created bright orange flames. As for samples 2 and 5,
2 burns on the stick and 5 had no reaction. Finally for "Test E"
samples control, 1, and 3 fizzed, while the other samples 2, 4,
and 5 had no change.
Due to missing the lab I probably didn't learn as
much as I would have with hands on experience, but I did learn
that just because two substances look the same does not mean they
have the same chemical properties or are basically the same. The
lab proved this hypothesis correct by majority of the substances
having many different effects. I did expect this just from prior
labs in my old school. Since I was not present for the lab I
can't really judge it but I guarantee I would have liked it, it
actually sounds pretty cool. I really enjoy this class and feel
the labs help me understand better.
The purpose of this lab was to show that not all
substances that look alike have the same chemical properties or
are the same thing. In the lab we as students had to find the
culprit of a crime by matching the chemical on them to the one
that it was all had a different substance so only one could be
the convicted. The control in the experiment was a white powder
of fine texture, dissolved easily in water did not burn but put
moisture on the mouth of the test tube, created a bright orange
flame when place in fire and fizzed/bubbled when placed in with
an acid solution. Based on everything observed there is no doubt
Suspect #3 is guilty for the crime.
All of the data in the lab was based on observations.
All of which were chemical or physical. The chemical properties
were not as easy to point out as the physical some examples of
the chemical were when some of the substances placed in flame
created colored light, while others did not. An example of
physical properties is the fact that most of the chemical
dissolved in water.
My guesses on the chemicals identities are based on
the data obtained in lab. Sample 1 was still unknown to me.
Sample 2 was powdered sugar this guess is based on while it was
burning it smelt like burning marshmallows. The acid solution was
vinegar and since sample 3 fizzed in it and because of its
texture I would say that sample 3 is baking soda. Sample 4 might
have been salt because it did not burn or create smoke. Last of
all Sample 5 could have been flour because it did not melt and
was insoluble in water.
The lab was very helpful in showing the difference
between chemical and physical properties. It taught that because
two substances look alike doe not mean the have all of the same
properties. It was rather fun too and there was a limited chance
of causing an error in the information. Over all the entire lab
was a very fun learning experience!