chemistry?

Question

what is the difference between an empirical formula and a molecular formula?

Answer 1

In chemistry, the empirical formula of a chemical compound is a simple expression of the relative number of each type of atom (called a chemical element) in it. An empirical formula makes no reference to isomerism, structure, or absolute number of atoms. Empirical formulas are the standard for ionic compounds, such as CaCl2, and for macromolecules, such as SiO2. The term empirical refers to the process of elemental analysis, a technique of analytical chemistry used to determine the relative percent composition of a pure chemical substance by element.

In contrast, the molecular formula identifies the absolute number of atoms of such element to be found in each discrete molecule of that compound.

For example, n-hexane, a chemical compound has the molecular formula CH3CH2CH2CH2CH2CH3, implying that it has a straight chain structure, 6 carbon atoms, and 14 hydrogen atoms. Hexane's molecular formula is C6H14, and its empirical formula would be C3H7 showing a C:H ratio of 3:7.

A chemical formula (also called molecular formula) is a concise way of expressing information about the atoms that constitute a particular chemical compound. For molecular compounds, it identifies each constituent element by its chemical symbol and indicates the number of atoms of each element found in each discrete molecule of that compound. If a molecule contains more than one atom of a particular element, this quantity is indicated using a subscript after the chemical symbol (although 19th-century books often used superscripts). For ionic compounds and other non-molecular substances, the subscripts indicate the ratio of elements in the empirical formula.

Answer 2

Empirical formula is the simplest ratio of the atoms involved. Molecular formula is the actual combination of atoms.

Example: Benzene is C6H6 = molecular formula
Empirical formula is CH, meaning one carbon for every hydrogen.