Copper or Cu is a chemical element that occurs naturally.
The name copper is derived from “coper,” which is the old English name of copper. Coper is further derived from the Latin word ‘Cyprium aes,’ which means ‘a metal from Cyprus.’
In this article, we will discuss whether copper is a pure substance or not.
Further, we will review the concepts of pure substance, mixtures, elements, compounds, homogeneous and heterogeneous substances.
So, is copper a pure substance or a mixture? Yes, copper is a pure substance as copper has definite properties. It is made up of only one kind of atom. A substance having one or more atoms in the same proportion throughout the substance is a pure substance.
It is a d-block metal with atomic number 29. The electronic configuration of Cu is [Ar] 3s2 3p6 4s1 3d10. The electronic configuration is different from normal to attain a stable, fully filled d10 configuration.
It is reddish-brown in color and solid at room temperature. The melting point is around 1084.2°C.
The most significant source of copper is in minerals like bornite and chalcopyrite. Copper is one of the essential metals for the human body.
Cu reacts with atmospheric oxygen to form copper oxide, which is black in color.
Cu was the first metal with which alloy was made. Copper can be recycled quite easily, and almost 70% of the copper that we use has been recycled.
What is Matter?
There are various definitions of matter, but the simplest one is stated here.
The matter is anything that occupies space and has mass. The matter is further classified into solid, liquid, and gas based on the physical state of matter.
Similarly, the matter is classified into pure substances and mixtures on the basis of composition.
We will discuss the latter classification in this article.
What is a Pure Substance?
Pure substances have a fixed value of various properties like melting point, boiling point, density, etc. They are made of only one type of particle.
All pure substances are homogeneous, meaning that their composition remains uniform throughout the bulk.
Pure substances cannot be broken down any further to form different products. For example] gold, copper, silver, etc.
Pure substances are further classified as elements and compounds.
Pure substances are very useful. They are needed to manufacture medicines, prepare chemicals at an industrial scale, for scientific purposes, and maintain good human health.
What is a Mixture?
Mixtures are made from pure substances. Mixtures are formed when two or more pure substances (elements or compounds) combine together physically.
They can be separated back into the pure substances used to form the mixture because there is no chemical bonding.
When a pure substance is present in a mixture, its properties are retained.
There are no definite properties of a mixture. Their composition is variable.
For example, table salt and black pepper are kept together in a bowl, salt in water, etc.
Mixtures are further divided into homogeneous mixtures and heterogeneous mixtures.
Why is Copper a Pure Substance?
Copper is an element that falls under the category of a pure substance.
Just like a pure substance-
• Cu has definite properties like boiling point, melting point, etc.
• The composition of a copper element remains the same, no matter what the conditions are.
• It cannot be converted to anything simpler by any means.
Due to these properties, copper can not be considered a mixture.
What is an Element?
An element is a pure substance that cannot be broken down into anything simpler than itself by any means.
All atoms in an element are the same; they have the same number of protons in nuclei.
Each element has its unique properties.
Element is the basic form of matter or building blocks of matter.
For example] Cu, Ag, Au, etc.
What is a Compound?
A compound is also a pure substance. It is formed by combining two or more elements chemically in a fixed ratio by mass.
They can be broken down into simpler substances by only chemical means.
For example H2O, CuO, etc.
Is Copper a Compound or Element?
Copper falls under the category of an element as copper cannot be broken down any further.
All the atoms in a copper element have 29 protons in the nuclei. Copper is the building block for many copper compounds.
It is not a compound as there is only one type of atom in Cu.
What is a Homogeneous Substance?
A substance that has a uniform composition throughout the bulk is a homogeneous substance. It generally has a single phase.
For example,] a mixture of salt in water forms a homogeneous solution on mixing it thoroughly.
If we take out 1mL of this solution from any side, it will have the same composition. We cannot distinguish between salt and water.
Other examples are gold, silver, water, etc.
What is a Heterogeneous Substance?
A substance that has a non-uniform composition throughout the bulk is a heterogeneous substance. It has more than one phase.
For example, a mixture of salt in water forms a non-homogeneous solution if not mixed thoroughly. If we take out 1mL of this solution from any side, it will not have the same composition.
Solid salt and water can be distinguished.
Other examples are a mixture of salt and pepper, sand and screw, etc.
Pure substances are always homogeneous, but mixtures can be homogeneous or heterogeneous.
Homogeneous mixtures like saltwater in the example can easily be confused with a pure substance.
Is Copper a Homogeneous or Heterogeneous Substance?
Copper is a homogeneous substance as the composition remains uniform throughout the bulk.
Generally, all elements and compounds are homogeneous.
Is Copper Oxide a Pure Substance?
Yes, Copper Oxide is considered a pure substance.
Copper oxide is formed when Cu reacts with atmospheric oxygen. It is black in color.
The color of copper darkens with time due to the formation of CuO on the surface of Cu. CuO has a fixed composition by mass.
There is a chemical bond between Cu and O. CuO can be converted back to Cu when treated with hydrogen gas.
It cannot be an element because there is more than one kind of nuclei in the CuO sample. It cannot be a mixture because a chemical bond is formed between Cu and O.
It is a compound because the two elements are present in a fixed proportion by mass. A compound is a pure substance.
Properties of Copper
• Malleable -it can be hammered into thin sheets without breaking.
• Ductile- it can be drawn into wires.
• Sonorous- it produces a ringing sound when struck hard.
• Lustrous- a fresh surface of copper is shiny. After some time, a black layer of CuO is formed, and luster decreases.
• Soft- It can easily be cut using steel.
• It shows high thermal and electrical conductivity.
• Dense substance- copper has a density of 8.96g/cm3.
• Biostatic- it does not allow bacteria to grow near it.
• Copper has good tensile strength.
• Copper is not magnetic in nature. I have also written a specific article on it. Check out the magnetism of copper.
• Copper compounds can act as a catalyst in various reactions.
For example, CuCl2 catalyzes the synthesis of acrylonitrile from acetylene and hydrogen cyanide.
• Copper forms various compounds in +1 and +2 states.
• It reacts with atmospheric oxygen according to the following reaction
2Cu + O2 ➔ 2CuO
• Copper turns green on exposure to moist air because of its reaction with water, carbon dioxide, and oxygen.
• Copper has low reduction potential than hydrogen. Therefore it does not react with acids. Check out does copper reacts with acid.
Uses of Copper
Copper finds its use in various domains. Some of them are
1. Pure copper is mixed with other metals to form alloys that are commonly used. • Coins of some countries are alloys of copper
• Gold jewelry is actually an alloy of gold and Cu because gold is very soft to be used as a jewel.
• Tin and copper form bronze.
2. Copper is often drawn into wires and used in electrical equipment like motors due to its properties of ductility and conductivity.
3. Copper is used in construction
4. Various industrial machinery like heat exchangers employ copper in them.
5. Copper Sulphate is made from Cu, which is used as
• Agriculture poison
• Algicide in water purification.
6. An aqueous solution of copper sulfate is used as Fehling A reagent.
It is used in differentiating between aldehydes and ketones. Cu has various such uses in the laboratory.
Copper is a pure substance.
Pure substances are further classified into elements and compounds.
Cu falls under the class of elements.
Pure Substances and elements are homogeneous in most cases, and hence Cu is homogeneous. CuO is a pure substance and belongs to the class of compounds.
Cu is a very useful element for industries and human health.
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