Difference Between Empirical and Molecular Formula (With Table)

Chemical formulas were first derived by determining the masses of all the components that combine to create a molecule, leading to the development of two key types of chemistry formulae: molecular formula and empirical formula. Both of these show the atoms present in a molecule but showcase and focus on different key features.

Empirical Formula vs Molecular Formula 

The difference between an empirical and molecular formula is that an empirical formula cannot get the exact measurement of the molecular mass, whereas the molecular formula can get the exact molecular mass. The empirical formula is the easiest ratio possible of the atoms, and the molecular formula provides you with the exact number of atoms. 

The empirical formula aims to show the atoms of a molecule in their simplest ratio. It can also help predict the type of atoms that are in the ionic compound and the repeating units in a polymer. It can be used for crystalline ionic compounds, simple molecules, polymers, etc. 

On the other hand, the molecular formula gives an exact quantity of atoms in a molecule. It is the formula that consists of the integer quantity of each atom that you calculated or that you are given. It can be used for covalent compounds but cannot be used for ionic compounds or macromolecules. 

Comparison Table Between Empirical and Molecular Formula 

Parameters of Comparison Empirical Formula Molecular Formula 
Definition It is the simplest form of formula that can be used for a molecule. It is the formula that shows the type of atoms and the number of each atom present in the molecule. 
Uses Used for crystalline ionic compounds, simple molecules, polymers, etc. Used for covalent compounds but cannot be used for ionic compounds or macromolecules. 
Molecular Mass It cannot measure the exact molecular mass. It can measure the exact molecular mass. 
Theory It gives the simplest ratio of a molecule’s atoms. It gives the exact number of atoms in a molecule. 
Predictions It can predict the type of atoms that are in the ionic compound and the repeating unit in a polymer. It can predict oxidation numbers in an atom, their reactions, and the end products achieved. 

What is Empirical Formula? 

Empirical formulas are the simplest type of molecular formulas that may be written. It displays the atom types in the molecule but does not provide the actual number of each atom. Rather, it offers the molecule’s simplest integer ratio for each atom. 

It is the most basic formula for a compound, defined as the ratio of subscripts of the least whole number of components in the formula. 

The simplest ratio of components in a molecular molecule is shown by the empirical formula. To create the formula for an ionic compound, we can just swap the charges of each icon, which immediately provides the number of ions in the molecule. For macromolecules, we may also create empirical formulations. 

When formulating empirical formulas for polymers, we put the repeating unit first, then the letter “n” to indicate that the polymer can have n repeating units. The empirical formula, on the other hand, cannot be used to determine a molecule’s mass, structure, or isomers, but it is helpful for analytical reasons. 

For example, Glucose has CH2O as its empirical formula, and the molecule formula for the same is entirely different. Ionic compounds in their crystalline form are usually shown with the help of an empirical formula. For example, in a NaCl crystal, we just the empirical formula since we cannot state the exact number of atoms. 

What is Molecular Formula? 

The kind of atoms and the number of each atom associated with a molecule are represented by molecular formulas. As a result, it determines each atom’s correct stoichiometry. The atoms are represented by symbols, which are displayed in the periodic table.  

Furthermore, the atom numbers should be written as subscripts. Some molecular formulae are neutral (no charge), but if there is one, it can be shown as a superscript on the right side. The integer quantities of the atoms are included in the subscript when formulating a formula.  

It’s a formula created from molecules that represents the total number of individual atoms found in a compound’s molecule. The quantity and kind of atoms that make up a molecule are represented in the form of a molecular formula. It is a depiction of the compound’s actual whole number ratio between its constituent parts. 

In chemical processes and when writing any chemical information, we usually utilize the molecular formula. We can learn a great deal about a molecule merely by glancing at its molecular formula.  

We can also compute the exact molecular mass, for example. Also, if it’s an ionic substance, we can anticipate which ions will be released and how many will be released when it dissolves in water. 

Main Differences Between Empirical and Molecular Formula 

  1. An empirical formula shows the simplest version of a formula of a molecule, whereas a molecular formula shows the type and quantity of atoms present in that molecule. 
  2. Empirical formulas can be used for crystalline ionic compounds, simple molecules, polymers, etc. Molecular formulas can be used for covalent compounds. 
  3. An empirical formula cannot measure the exact molecular mass, whereas the molecular formula can. 
  4. The simplest ratio is shown by empirical formulas, and the exact amount of atoms is shown by molecular formulas. 
  5. An empirical formula can predict the type of atoms that are in the ionic compound and the repeating unit in a polymer. A molecular formula can predict oxidation numbers in an atom, their reactions, and the end products achieved. 

Conclusion 

We can write an empirical formula for a certain molecule or macromolecule, but the molecular formula is the more detailed version of it with more comprehensive information. 

Molecular formulae indicate the kind of atoms and the quantity of the atoms connected in the molecule, whereas empirical formulas show the simplest form of formulas that we may write for a molecule.  

As a result, the primary distinction between empirical and molecular formulae is that empirical formulas only provide the simplest atom ratios, but molecular formulas provide the actual quantity of the atoms included in a molecule.  

References 

  1. https://www.sciencedirect.com/science/article/abs/pii/0584854787800666 
  2. https://www.sciencedirect.com/science/article/abs/pii/0003267086800216 
2D vs 3D x
2D vs 3D