In balancing a chemical equation, why can you change coefficients, but not subscripts?

Short Answer

Expert verified
'Coefficients' represent the number of units of each compound involved in the reaction and can be manipulated to balance a chemical equation, ensuring the conservation of mass as per the Law of Conservation of Matter. However, 'subscripts' define the composition of the compound itself, and changing them would create a completely different substance, this is not permitted in balancing chemical equations.

Step by step solution

01

Understand Chemical Equations

A chemical equation represents a chemical reaction where reactants are transformed into products. It's written in the form of symbols and formulas, where each element is represented by its specific symbol (like H for Hydrogen, O for Oxygen) and a chemical formula represents a compound. For example, in the equation H2 + O2 → H2O, H2 and O2 are reactants and H2O is the product.
02

Definition of Coefficients and Subscripts

In a chemical equation, numbers appearing before the symbols or formulas are called coefficients while numbers written at the lower right corner of the symbols are called subscripts. In the equation 2H2 + O2 → 2H2O, 2 in front of H2 and H2O are coefficients and the 2 in H2O is a subscript, which indicates the number of that particular element in the molecule.
03

Difference between Coefficients and Subscripts

Coefficients represent the number of molecules (or moles) involved in the reaction, whereas subscripts show the number of atoms of each element in a molecule. Changing a coefficient essentially changes the amount of a molecule in the reaction. On the other hand, changing a subscript would change the identity of the substance, as it would alter the number of atoms of an element in the molecule, thus forming a completely different compound.
04

Explanation of Why we Change Coefficients not Subscripts

In order to balance a chemical reaction, the strategy is to ensure that there is the same amount of each kind of atom on both sides of the equation. This is achieved by changing the coefficients, or the number of units of each compound. Changing subscripts, on the other hand, would change the actual substance being considered in the reaction, which is not what we are aiming to do when we balance a chemical equation.

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