What is the significance of subscripts in chemical formulae?

Subscripts in chemical formulae indicate the number of atoms of each element present in a compound.

In a chemical formula, each element is represented by its chemical symbol, and the number of atoms of each element in the compound is shown as a subscript. For instance, in the formula for water, H2O, the subscript '2' after the 'H' indicates that there are two hydrogen atoms in each molecule of water. The oxygen atom does not have a subscript, which means there is one oxygen atom in each water molecule.

Subscripts are crucial in understanding the composition of a compound. They provide information about the ratio of atoms in a compound, which is fundamental in stoichiometry - the study of the quantitative relationships between the amounts of reactants used and products formed in a chemical reaction. For example, the formula for glucose, C6H12O6, tells us that one molecule of glucose contains six carbon atoms, twelve hydrogen atoms, and six oxygen atoms.

Moreover, subscripts can also indicate the state of matter of a substance in a reaction. For instance, (s) for solid, (l) for liquid, (g) for gas, and (aq) for aqueous. These are not to be confused with the subscripts that denote the number of atoms.

It's important to note that subscripts should never be changed when balancing chemical equations. Changing a subscript alters the identity of the substance, while balancing an equation only involves adjusting the number of molecules or ions of a substance, which is indicated by coefficients, not subscripts.

In summary, subscripts in chemical formulae play a vital role in conveying the precise composition of compounds, aiding in the understanding of chemical reactions and stoichiometry.