What is a pure substance?
A pure substance is a substance composed of only one type of atom or molecule and cannot be chemically broken down. In other words, a pure substance consists of only one type of atom or molecule and is not found mixed with any other substance.
For example, pure water consists only of H2O molecules, which are made up of hydrogen and oxygen atoms. Pure sodium chloride (table salt) consists only of NaCl molecules, which are made up of sodium and chloride atoms.
Pure substances are divided into two main categories: elements and compounds. Elements are pure substances composed of only atoms of the same type, such as gold, silver, oxygen, and hydrogen. Compounds, on the other hand, are pure substances formed by the combination of atoms of at least two different elements, such as water, salt, carbon dioxide, and sugar.
Pure substances have specific properties, and these properties depend on the structure of the atoms or molecules. Understanding the properties of pure substances is one of the fundamental principles of chemistry and plays an important role in industry, medicine, engineering, and many other fields.
What are the properties of pure substances?
The properties of pure substances are as follows:
- Fixed Composition: Pure substances have a constant composition. That is, the composition of a substance is always found in the same proportions and in the same molecular form.
- Fixed Features: Pure substances possess specific physical and chemical properties. These properties depend on the atomic or molecular structure of the substance and remain constant. These properties include, for example, density, melting point, boiling point, and chemical reactivity.
- Homogeneous: Pure substances have a homogeneous structure. This means that the composition at any point in the substance is similar to its composition at any other point.
- Differentiation: Different substances can be distinguished because pure substances have their own unique properties.
- Chemical Change: Pure substances can undergo chemical reactions to form new substances. However, this occurs through the rearrangement of the atoms or molecules of the substance, resulting in a change in its composition.
- High Purity: Pure substances can be obtained with high purity when separated from other substances. This is important in the research and industrial applications of pure substances.
- Specific Physical Characteristics: Pure substances have certain physical properties that make them easy to distinguish from other substances. For example, the high boiling point of pure water makes it easy to separate from other substances.
Examples of pure substances
Here are some examples of pure substances:
- This: Pure water is the pure form of a compound formed by the combination of hydrogen and oxygen atoms in a fixed ratio.
- Gold: Gold is a pure metal and is mostly found in its pure form in nature. Therefore, gold is an example of a pure substance.
- Oxygen: Oksijen, saf bir elementtir ve havanın yaklaşık %21’ini oluşturur. Oksijen, bir molekül halinde veya diğer elementlerle bileşik halinde bulunabilir, ancak saf halde de bulunabilir.
- Sugar: Sugar is a pure compound formed by the combination of carbon, hydrogen, and oxygen atoms in specific ratios.
- Salt: Salt is a pure compound formed by the combination of sodium and chloride ions in fixed ratios.
- Iron: Iron is a pure metal and is found in nature as iron ore. The ore can be transformed into pure iron through a purification process.
- Nitrogen: Azot, saf bir elementtir ve havanın yaklaşık %78’ini oluşturur. Azot, bir molekül halinde veya diğer elementlerle bileşik halinde bulunabilir, ancak saf halde de bulunabilir.
Pure substances are classified as "Elements and Compounds".“ They are divided into two categories.
