What is the Difference Between Coefficient and Subscript?

The main difference between coefficients and subscripts lies in their roles within chemical equations and their representation of substances:

• Coefficients: These are the numbers placed in front of compounds or elements in a chemical equation. They indicate the number of moles of each substance involved in the reaction and can be changed to balance the equation. For example, in the chemical equation "N2 + 3H2 ⟶ 2NH3", the coefficients are 1 for nitrogen gas, 3 for hydrogen, and 2 for ammonia.
• Subscripts: These are the small numbers written below the element symbols in a chemical formula. They represent the number of atoms of each element within a molecule and cannot be changed without altering the chemical identity of the substance. In the example "N2 + 3H2 ⟶ 2NH3", the subscripts are 2 for nitrogen in nitrogen gas, 2 for hydrogen in hydrogen gas, and 1 for nitrogen and 3 for hydrogen in ammonia.

In summary, coefficients indicate the number of moles of each substance involved in a reaction and can be changed, while subscripts represent the number of atoms of each element within a molecule and cannot be changed without altering the chemical identity of the substance.

Comparative Table: Coefficient vs Subscript

The main difference between a coefficient and a subscript in a chemical equation lies in their representation of quantities:

• Subscripts: These are the small numbers written immediately after the atom or molecule they describe, indicating the number of atoms of that element in the molecule. For example, in the chemical formula $\ce{H2O}$, the subscript "2" indicates that there are two hydrogen atoms in the water molecule.

• Coefficients: These are the numbers written in front of compounds or individual elements, indicating the number of molecules or atoms of that substance in a reaction. For example, in the balanced chemical equation $\ce{2H2 + O2 -> 2H2O}$, the coefficient "2" in front of the hydrogen molecule $\ce{H2}$ indicates that there are two hydrogen molecules are reacting.

Here is a summary table comparing coefficients and subscripts:

In summary, coefficients are used to represent the number of molecules or atoms of a substance, while subscripts are used to represent the number of atoms of an element in a molecule. Changing the coefficient value changes the amount of molecules, whereas changing the subscript value changes the substance itself.