I know you've probably seen the demonstration wherein sugar is dehydrated by concentrated sulfuric acid. It is an interesting experiment that produces, among other products, an exciting pillar of carbonaceous matter.
So a few weeks ago I was browsing the literature and came across an article describing a version of this demonstration.
But instead of using large amounts of concentrated sulfuric acid, the authors used the heat produced by the oxidation of part of the sugar by potassium chlorate. I tried it and found it interesting enough to be worth a video.
This demonstration is one of my favorites involving copper chemistry since it is simple, it involves relatively harmless materials and produces a compound whose color differs from the traditional green and blue of copper compounds.
It is based on the fact that, when electrolyzing a concentrated solution of table salt in a divided cell using a copper anode, cuprous chloride is formed in the anolyte and a dilute solution of caustic soda is produced in the catholyte. By allowing the two liquids to mix, copper (I) hydroxide precipitates and the table salt is regenerated.
The cell consists of two plastic cups connected by a thin PVC tube. The anode is a copper wire and the cathode a steel plate. The power supply provides 24 volts, the voltage needed to overcome the high electrical resistivity of the cell.
After approximately one hour and twenty minutes of electrolysis, we have enough of the reagents needed to run the demonstration. Note the milky appearance of the liquid in the anolyte. This is due to the fact that cuprous chloride is practically insoluble in water. What we actually have is a suspension, that is, tiny particles of the compound floating through the liquid.
The liquid in the catholyte also has some whitish material present. This did not happen in my previous experiments with another brand of salt and I believe that this is due to calcium and magnesium contaminants precipitating their hydroxides.
If we add an ammonia solution to the cuprous hydroxide suspension, the color changes from bright yellow to blue and the solution loses its opacity. This is due to the formation of the diamine copper complex, which is soluble in water.
Now, if we add a small portion of calcium carbide to the solution, a new color change occurs and a copper compound with explosive properties precipitates. But that is a topic for another video. See you there!
In this article, an improvised-built Bunsen burner is presented. The materials and processes for the construction of this equipment are described and a quick introduction to the factors that affect the behavior of the flame is presented.
My alcohol lamp served me for a long time.It was possible to do almost anything with it, including melting small portions of lead or concentrating small volumes of sulfuric acid.
However, I felt the need for an apparatus in which it was possible to adjust the heating in a more comfortable way.The project now published fills this gap.
I thought that the air regulator, being made of plastic, would be one of the critical parts of this project.However, I found that:
1) The flame does not appear to burn inside the tube or even at the open end of it, there appears to be a millimeter interface between the lower end of the flame and the gas flow at the outlet of the tube.That is, the flame front does not seem to hit the metal at any time, but rather to burn a millimeter or less just above it.It is possible that this is a characteristic of this specific system and the low gas injection pressures involved.
2) The gas leaves the cylinder at a really low temperature and cannot exchange heat with the ambient before reaching the burner. In fact, in some moments, even in full operation, it is possible to feel the bottom of the aluminum tube slightly cold
3) The use of a heatsink as a base was really efficient in removing any residual heat before it reached the regulator.
The gas regulator is a point that deserves continuous attention.It worked incredibly well and tests carried out under water proved that there were no leaks of any kind.However, it is still a homemade regulator being used to extract flammable gas from a pressurized cylinder. Since the device will be used exclusively outdoors, small leaks of gas at the regulator junctions - more dangerous for this poor chemist's wallet than for his safety, I would say - can be induced by the vibrations of daily use.I intend to replace it with a suitable regulator as soon as possible.
Having said all that, I am happy for my new equipment.Heating things up to moderate temperatures will become a little easier now.
This article describes a simple - yet efficient - holder/stand/clamp designed to hold glassware during different procedures in the laboratory. This is a project made with recycled materials in an approach of low complexity and reasonable robustness.
It is quite useful equipment. The clamp may not have the most suitable design, but considering that it was built with materials that would normally go to waste, the results were satisfactory.
Some pictures:
Miscellaneous
Having returned to practicing chemistry as a hobby after so many years has shown me that, unlike what I used to do as a teenager, some aspects of safety need to be observed more rigorously.My next goal is to build a small fume hood.Nothing too elaborate, since I currently don't have the space necessary to set up an adequate laboratory, but a structure that is capable of capturing potentially harmful gases for the operator and / or whose disposal without prior treatment would be environmentally irresponsible.
This was also the first narrated video I made.It was a little disappointing to realize that my spoken english is still quite primitive.However, I don't think that much can be done besides forcing me to write and speak in this language.Certainly more fluency in pronunciation will come over time.
A small collection of random videos from some experiments.
Soon I will publish about the syntheses that I have/intend to carry out
in the amateur environment.
Why did I create this channel? Well, I've been experimenting for at
least 15 years. I did some interesting things that I would like to share
with other amateur scientists. Of course, this will also allow me to
improve my english (which is currently at most reasonable).
There are many ways to understand the universe (in whole or in part)
that you can fall in love with. After I got to know applied chemistry,
all the others stayed in the background. Ever since I was a kid I
always wanted to know how this or that worked, I always wanted to "break
to see what's inside". Bad luck for the RC cars and things like that I
got.
It's been over 15 years since I first experienced this feeling, but I
don't think things have changed much. I keep "breaking to see what's
inside".
My intention with this blog is to make science a little better known as
it really is, magnificent as a whole.
I hope that the information available here will be useful to you in some
way, and that you will use it as intelligently as possible.
Some of the experiments published here have been studied and/or refined on a small scale by me over periods of 4 years or more.They are, therefore, the result of intense scientific research and enormous dedication, seasoned with an infinite desire to understand the universe around me.Science is fascinating, and has a practical side to everyday life that often goes unnoticed.It is not necessary for everyone to have a laboratory at home, but it is highly recommended and beneficial that Science and the implications that result from its discoveries are routinely discussed and evaluated by everyone.Whether in a school environment, or in a casual meeting of friends.
