Many students wonder if a molecule and a compound are the same. Well, there is a great difference between the two.
A molecule can be defined as a group of two or more than two atoms that are bonded together chemically.
A compound can be defined as a pure substance that is made of two or more than two different elements that are combined chemically in a fixed ratio.
A compound is a type of molecule, but a molecule is not a compound.
In this article, we will study the difference between a Molecule and a Compound.
1. Molecule
A molecule is a chemical compound consisting of two or more than two atoms that are held together by chemical bonds.
The atoms in a molecule can be the same or different and can be in various combinations to form different types of molecules.
1.1 Examples of molecules
Some common examples of molecules are as follows:
- Water (H2O)
- Carbon dioxide (CO2)
- Oxygen (O2)
- Glucose (C6H12O6)
- Ethanol (C2H5OH)
- Table salt (NaCl)
- Acetic acid (CH3COOH)
- Ascorbic acid (C6H8O6)
- Triglycerides (C55H104O6)
- Ammonia (NH3)
- Chlorine gas (Cl2)
- Methane (CH4)
- Nitrogen gas (N2)
- Hydrogen peroxide (H2O2)
- Sulfuric acid (H2SO4)
1.2 Types of Molecules
There are many different types of molecules, but some common categories include the following:
Organic molecules: These are molecules that contain carbon atoms and are found in living organisms. Examples include carbohydrates, lipids, and proteins.
Inorganic molecules: These are molecules that do not contain carbon atoms or are not found in living organisms. Examples include water, sulphuric acid, and ammonium nitrate.
Macromolecules: These are large molecules made up of many smaller subunits. Examples include proteins, nucleic acids, and polysaccharides.
Simple molecules: These are small molecules that are made up of only a few atoms. Examples include water, carbon dioxide, and oxygen.
Complex molecules: These are large molecules that are made up of many atoms and have a more complex structure. In these types of compounds, coordinate covalent bonds are involved, and some of these compounds are carcinogenic in nature. Examples include proteins, DNA, and enzymes.
Ionic molecules: These are molecules that are held together by ionic bonds, which are formed between atoms that have opposite charges. Examples include salt (NaCl), and magnesium oxide (MgO).
Covalent molecules: These are molecules that are held together by covalent bonds, which are formed between atoms that share electrons. Examples include water (H2O), and methane (CH4).
2. Compound
A compound can be defined as a pure substance that is made of two or more than two different elements that are combined chemically in a fixed ratio of mass. Compounds can be either organic or inorganic.
A compound’s elements are chemically bonded and cannot be easily separated by physical means. They have distinct properties and characteristics that are different from the properties of the individual elements that make them up.
Compounds can be broken down into their individual elements by chemical reactions, such as combustion, acid-base reactions, electrolysis, and so on.
2.1 Examples of Compounds
Some of the common examples of compounds include:
- Water (H2O) – It consists of hydrogen and oxygen.
- Carbon dioxide (CO2) – It consists of carbon and oxygen.
- Table salt (NaCl) – It consists of sodium and chlorine.
- Sucrose (C12H22O11) – It consists of carbon, hydrogen, and oxygen.
- Ethanol (C2H5OH) – It consists of carbon, hydrogen, and oxygen.
- Acetic acid (CH3COOH) – It consists of carbon, hydrogen, and oxygen.
2.2 Types of Compounds
There are many different types of compounds, but some common categories include the following:
Organic compounds: These compounds contain carbon atoms and are found in living organisms. Examples include carbohydrates, lipids, proteins, and DNA.
Inorganic compounds: These compounds do not contain carbon atoms or are not found in living organisms. Examples include water, salts, acids, and bases.
Ionic compounds: These compounds are made of positively and negatively charged ions that are held together by electrostatic forces of attraction. Examples include sodium chloride (NaCl) and calcium oxide (CaO).
Covalent compounds: These compounds are made up of atoms that share electrons in covalent bonds. Examples include water (H2O) and methane (CH4).
Molecular compounds: These compounds are made of molecules that are held together by weaker intermolecular forces. Examples include hydrogen chloride (HCl) and sulfur dioxide (SO2).
Complex compounds: These compounds are made up of a central atom or ion that is surrounded by other atoms or ions in a specific arrangement. Examples include coordination compounds such as [Fe(CN)6]-4 and [Co(NH3)6]3+.
Hybrid compounds: These compounds are made up of a combination of ionic and covalent bonds. Examples include oxides such as CO2, SO2, and NO2.
Also Refer: Properties of Compounds
3. Difference between a Molecule and a Compound
| Molecule | Compound |
| A molecule is a group of atoms that are chemically bonded together but not necessarily in a fixed ratio. | A compound is a substance made up of two or more different elements that are combined chemically in a fixed ratio. |
| It can be made up of the same or different elements. | It is always made up of two or more different elements. |
| In some cases, it is possible to separate molecules by physical means. | Compounds can only be separated by chemical means. |
| It is not possible to count the molecules. | It is possible to count the atoms that are present in a compound. |
| Molecules cannot combine with other molecules to create new substances. | A compound can combine with other compounds to create new substances. |
| Molecules cannot be seen with the naked eye. | Compounds can easily be seen with the naked eye. |
| Examples: H2, O2, CO2, CH4 | Examples: H2O, NaCl, C6H12O6, CH3COOH |
- Compounds have a definite chemical composition, and Molecules do not.
- A compound includes two or more constituents, whereas a molecule has at least one element.
- Molecules can be composed of atoms in a single element, whereas a compound is composed of at least two elements.
FAQs
Are all compounds molecules?
No, not all compounds are molecules. A compound is a substance made up of two or more different elements that are chemically combined in a fixed ratio, while a molecule is a group of two or more atoms that are chemically bonded together.
Can a molecule contain only one type of element?
Yes, a molecule can contain only one type of element. For example, diatomic molecules such as O2, N2, and H2 are not compounds because they are made up of only one type of element.
Is a compound always made up of molecules?
Not always. Compounds can be made up of atoms or ions. For example, sodium chloride (NaCl) is a compound made up of sodium ions (Na+) and chloride ions (Cl–), not molecules.
Do molecules and compounds have different properties?
Molecules and compounds can have different properties depending on the atoms or ions that make them up and how they are bonded together. For example, H2O (water) is a compound made up of hydrogen and oxygen molecules, it’s a liquid at room temperature, while O2 is a molecule made of two oxygen atoms, it’s a gas at room temperature.