A chemical substance is a very interesting topic of chemistry. We will discuss all of them in detail in this article. The matter having the constant chemical composition and characteristic properties is called a chemical substance.
Usually, chemical substances can not be separated into their basic elements. There are three types of chemical substances: simple substances, chemical compounds and alloys.
Chemical substances are called pure or mixture. For example, pure water, diamond, gold, table salt, refined sugar etc. are pure substances. But in reality, usually, we don’t find any substance as a pure form because there are always some impurities in it.
Chemical substances can be solid, liquid, gas, or plasma and their state can be changed with different pressure, time, or temperature.
Pure Substances and Examples of substances
Substances that have only one kind of particle and no impurities are called pure substances. In other words, pure substances are having a constant composition and structure. A pure substance is often referred to as a “chemical substance”.
All elements are pure substances. But a pure substance does not have to be of a single element or compound. Iron, silver, gold and aluminium are some examples of pure substances. Pure substances are the base of all substances.
Pure substances are classified into two categories: elements and compounds. A substance with only one kind of atom is known as element. Elements can be metals, non-metals or metalloids. When two or more elements are combined chemically in a fixed ratio, it becomes a compound.
Compounds can be broken down into separate elements by some methods. You are advised to check https://www.vedantu.com/chemistry/pure-substances to know more about pure substances in detail.
Pure substances are needed to manufacture medicines, to prepare chemicals in industry, for scientific purposes and to maintain the good health of human beings.
Mixtures and Examples of mixtures
When two or more different substances are mixed but not chemically joined together, it is known as a mixture. For example, a salt solution is a mixture of salt and water. Mixtures can be classified as homogeneous and heterogeneous.
A homogeneous mixture or a solution is the same throughout the sample. While a heterogeneous mixture’s configuration varies from spot to spot within the sample and consists of lots of variety.
Smog (smoke and fog), seawater (water and salt), seafoam (oxygen and water), gun powder (potassium nitrate, sulfur, and carbon), mud (dirt and water), cement (sand, water and gravel) etc are few more examples of mixtures. Mixtures can be classified into solutions, suspensions, colloids and emulsions too.
A mixture’s components can be separated from one another. A mixture is an impure substance. It has no formula either. It can be fixed in any ratio. Mixtures do not have specific properties. The properties of the mixtures are a result of the average properties of all the constituents. Mixtures usually formed as a result of a physical change.
Comparing Pure Substances and Mixtures
There are a few similarities and differences between pure substances and mixtures when we compare both. Some of them are as below: Purity of pure substance is pure while mixtures are impure.
You cannot separate pure substances by a physical process but it is possible to separate the mixture by evaporation, magnetic separation, etc. methods. Pure substances have a fixed composition while mixtures have a variable composition
Pure substances have a fixed melting and boiling point while it differs in mixtures. Properties of pure substances are fixed while mixtures have varying physical and chemical properties. Pure substances are made up of a single element while a mixture is a combination of two substances or elements.
Characteristics of Pure Substances
Pure substances are homogeneous because they are made up of only one type of atom or molecule. It has definite properties and composition. Composition of pure substance does not vary. It has a constant or uniform composition throughout
The substances have a fixed boiling and melting point. They have fixed colour, mass, density, volume, hardness, electrical conductivity and heat capacity. It cannot be separated into other kinds of matter by any physical process. It can change states without altering or changing the identity of the substance. They normally participate in a chemical reaction to form predictable products.
Types of Pure Substances
Pure substances are divided into two categories: elements and compounds. Substances that are made up of a single kind of atom and which can not be broken down further is known as elements.
Iron, silver and gold are examples of elements. When we combine two or more elements and chemically combine them in a fixed proportion, it is called a compound. Water, vinegar and carbon dioxide are examples of compounds. Neither elements nor compounds can be separated by physical methods.
Elements are further classified into three different types: metals, non-metals and metalloids. The elements that conduct heat and electricity and are malleable and ductile, are known as metals. For example, iron, copper, zinc, tin, gold, silver, platinum, etc.
Elements that do not conduct heat or electricity and are neither malleable nor ductile but are brittle, are known as non-metals. For example, oxygen, chlorine, sulphur, hydrogen, nitrogen, phosphorus, etc. The elements which possess the characteristic of both metals and non-metals are known as metalloids.
Metalloids are also known as semi-metals. For example, boron, tellurium, germanium, arsenic, antimony, selenium, etc.
Compounds are further classified into two types: inorganic compounds and organic compounds. Compounds that are obtained from non-living sources like seawater, rocks, earth crust, etc. are known as inorganic compounds. For example, H2O (water), H2SO4 (sulphuric acid), NaCl (sodium chloride), CaCO3 (calcium carbonate), etc.
Compounds containing carbon and a few other elements like hydrogen, oxygen, nitrogen, sulphur, halogens, etc. are known as organic compounds. Organic compounds are usually obtained from plants and animals. Organic compounds can be synthesized too. For example, alcohol, sugar, fats, benzene, oils, urea, proteins, methane, etc.
We have seen chemical substances and mixtures in this article with their characteristics, types, similarities, differences, etc. in detail with examples here. We hope you enjoyed knowing about substances and found it helpful.