Chapter 6.3, Problem 3RQ

Interpretation Introduction

Interpretation: The information required to determine the molecular formula from an empirical formula of a compound needs to be explained.

Concept Introduction: The molecular mass of compound is the sum of atomic mass of all the atoms present in the given chemical compound. Here the molecular formula represents the exact number of all bonded atoms in the compound.

Whereas empirical formula can be defined as the simplest positive integer ratio of all bonded atoms in the compound.

Answer to Problem 3RQ

Molecular mass is required to get the molecular formula from empirical formula.

Explanation of Solution

The empirical formula gives the simplest positive integer ratio of all bonded atoms. Thus it does not give the exact number of bonded atoms in the molecule.

The molecular formula can be determined with the help of empirical formula and molecular mass as given.

  $\begin{array}{l}\text{n = }\frac{\text{molecular mass}}{\text{mass of empirical formula}}\\ \text{Molecular formula = [Empirical formula]}\times \text{ n}\end{array}$

Conclusion

  $\begin{array}{l}\text{n = }\frac{\text{molecular mass}}{\text{mass of empirical formula}}\\ \text{Molecular formula = [Empirical formula]}\times \text{ n}\end{array}$