Which statement best describes the relationship between an empirical formula and a molecular formula?

• A. The empirical formula represents the simplest whole-number ratio of atoms in a compound, while the molecular formula shows the actual number of atoms of each element in a molecule.
• B. The empirical formula is always identical to the molecular formula for all compounds.
• C. The empirical formula provides information about the structure of the molecule.
• D. The empirical formula always contains the same number of atoms as the molecular formula.

Answer: (A)

Verified step by step guidance

1. Understand that the empirical formula of a compound represents the simplest whole-number ratio of the atoms of each element present in the compound. It does not necessarily show the actual number of atoms in a molecule, but rather the relative proportions.
2. Recognize that the molecular formula shows the actual number of atoms of each element in a single molecule of the compound. This means it can be a multiple of the empirical formula.
3. Note that the empirical formula is derived by dividing the subscripts in the molecular formula by their greatest common divisor to get the simplest ratio.
4. Understand that the empirical formula does not provide direct information about the structure or arrangement of atoms in the molecule; it only gives the ratio of elements.
5. Conclude that the correct relationship is: the empirical formula is the simplest ratio of atoms, while the molecular formula shows the exact number of atoms in a molecule, which may be the same as or a multiple of the empirical formula.