Hello, everyone.
Today, I will tell you about the first of the metals mastered by man:
Copper.
In the periodic table of chemical elements, copper is in the 11th group,
the so-called trio of the precious metals:
copper, silver, and gold.
According to the archaeological data,
humanity started creating the first copper products
in the 6th or 7th millennium B.C.
That is around 9,000 years ago.
Due to its low activity, copper was the first
metal acquired by humans in its purest form.
The process of obtaining copper is very simple.
It starts with a malachite ore, or
also known as a basic copper carbonate.
Then, it's mixed with charcoal, and after that, it's ignited.
The result is carbon monoxide gas,
which recovers copper from malachite to metallic state.
The resulting copper can be melted,
and then processed to then create something out of it.
The Latin name for copper, cuprum, comes from the east land of Cyprus,
where there were rich deposits of malachite ore.
Copper is sometimes found in the form of nuggets covered with patina,
which is a basic copper carbonate.
To demonstrate the chemical properties of copper,
let's take the same basic carbonate, or malachite ore,
but, [unintelligible] as the ones you can find in nature.
When ammonia is being mixed with the basic copper carbonate,
it forms a soluble ammonia complex of copper.
This reaction can be used to clean copper products from patina,
however, instead of ammonia,
the smell of which will make you want to run away as fast as you can,
you could use a less smelly substance,
Try [unintelligible], as it's also a good complexing agent.
Metallic copper is a very stable and low-activity metal.
That is why the spires of all churches were covered with copper sheets,
as it protects the roof for many years.
Metallic copper is not soluble in dilute sulfuric and hydrochloric acids,
as it's located after hydrogen in the reactivity series of metals.
However,
copper reacts quite actively with concentrated nitric acid,
forming nitrogen dioxide, a brown gas with an unpleasant odor,
and copper nitrate.
If we look at the copper compounds,
the most common copper salt in everyday life is of course copper sulfate.
It's used for the disinfection of plants from insects,
and also in analytical chemistry.
If you add sodium hydroxide to copper sulfate,
the copper hydroxide precipitate will fall out,
which can be used to determine the presence of sugar in fruits.
Let's add some grated apple into the glass of copper hydroxide,
and then heat the mixture.
Over time, the glucose contained within the apple juice
recovers copper by a violent state
[unintelligible]
and after a while, the solution becomes orange.
In the cup, an oxide of copper (I) was formed
from the copper hydroxide.
That is a qualitative reaction that shows a presence of glucose in the apple.
The oxide of monovalent copper dissolves in ammonia solution,
forming monovalent copper-ammonium compex.
Compounds of the monovalent copper are colorless,
but,
with oxidation of the solution with hydrogen peroxide,
the solution turns blue due to the oxidation of copper
[tossed?] by a violent state.
Also, if you mix blue copper hydroxide and glycerol,
the solution will turn bright blue
due to the formation of copper glycerite,
which is also a qualitative reaction for checking polyhydric alcohols.
In general, copper compounds are used in many analytical reactions,
which can determine even the alcohol concentration in a solution.
There is also another interesting reaction
which can be used to obtain a copper mirror.
In the cup with the solution of copper sulfate,
a powerful reducing agent is poured.