Which of the following is not a compound? This question often arises in the field of chemistry, where understanding the difference between elements, compounds, and mixtures is crucial. In this article, we will explore various substances and determine which one does not fit the definition of a compound.
Compounds are substances formed by the chemical combination of two or more different elements in fixed proportions. They have unique properties that are different from the properties of their constituent elements. On the other hand, elements are pure substances that cannot be broken down into simpler substances by chemical means. Mixtures, on the other hand, are combinations of two or more substances that are not chemically bonded and can be separated by physical means.
Let’s examine some examples to identify the substance that is not a compound:
1. Water (H2O): Water is a compound formed by the chemical combination of hydrogen and oxygen in a fixed ratio. It has unique properties, such as the ability to dissolve many substances and exhibit cohesion and adhesion.
2. Sodium chloride (NaCl): Sodium chloride, commonly known as table salt, is a compound formed by the chemical combination of sodium and chlorine. It has a crystalline structure and is an essential component of the human diet.
3. Carbon dioxide (CO2): Carbon dioxide is a compound formed by the chemical combination of carbon and oxygen. It is a greenhouse gas and plays a vital role in the Earth’s atmosphere.
4. Oxygen (O2): Oxygen is an element, not a compound. It consists of two oxygen atoms bonded together and is essential for the survival of most living organisms.
5. Ethanol (C2H5OH): Ethanol is a compound formed by the chemical combination of carbon, hydrogen, and oxygen. It is a flammable liquid with various applications, including as a fuel and a solvent.
Based on the definitions and examples provided, the substance that is not a compound is oxygen (O2). While it is a vital element for life, it does not meet the criteria of being a compound, as it is not formed by the chemical combination of different elements in fixed proportions.
