Question

Two substances have the same molecular and empirical formulas. Does this mean that they must be the same compound?

Short answer

Yes, if two substances have the same molecular and empirical formulas, they must be the same compound. This is because the molecular formula shows the actual number of atoms of each element present in a molecule, and the empirical formula shows the simplest whole number ratio of the atoms of each element. If both formulas are the same for both substances, it indicates that they have the same atoms in the same proportion, making them the same compound.

Step-by-step solution

Understanding molecular and empirical formulas

Molecular formula shows the actual number of atoms of each element present in a molecule of a compound. Empirical formula, on the other hand, shows the simplest whole number ratio of the atoms of each element present in a molecule.

Comparing similarities between molecular and empirical formulas

When comparing molecular and empirical formulas, it's crucial to determine if their composition is similar. If two substances have the same molecular formula, it suggests that they consist of the same elements in the same proportion and the same number of atoms. Additionally, having the same empirical formula implies that both compounds have the same simplest whole number ratios of the elements present.

Analyzing if the same molecular and empirical formulas can indicate the same compound

Since two substances with the same molecular formula have the same atoms in the same proportion, this means that they are the same compound. Furthermore, having the same empirical formula supports this conclusion, as it indicates the simplest whole number ratio of atoms in both compounds is the same. Thus, if two substances have the same molecular and empirical formulas, they must be the same compound.