Final answer:
Chemical formulas represent the composition of compounds, using element symbols and subscripts to indicate the number of atoms. They are essential in writing chemical equations that describe the reactants and products in chemical reactions.
Step-by-step explanation:
Chemical formulas are a method of expressing the composition of a chemical compound. They use element symbols from the periodic table to denote the different atoms present in the compound and have subscripts to indicate the number of each type of atom. For instance, in the chemical formula H2O, the symbol 'H' represents hydrogen, and 'O' represents oxygen, with the subscript '2' indicating that there are two hydrogen atoms for every one oxygen atom present.
Furthermore, chemical formulas are not just arbitrary collections of letters and numbers; they convey vital information about the substances involved in chemical reactions. For example, the formula CO2 signifies carbon dioxide, a compound composed of one carbon atom covalently bonded to two oxygen atoms. When writing chemical equations, these formulas are used to represent both the reactants and products involved in a chemical change, such as CH4 + 2O2 → CO2 + 2H2O to show the combustion of methane. This notation is essential in science because it provides a universal language for scientists to describe and understand chemical interactions precisely.