Chapter 8, Problem 42A

Interpretation Introduction

Interpretation: The differences between molecular formulas and structural formulas for molecular compounds.

Concept Introduction: Molecular formula is a way to express the chemical composition of a molecule. In this formula, all the atoms present in the molecule are written in their symbolic representation. For example, the molecular formula of sodium chloride is NaCl.

Explanation of Solution

The molecular formula tells about the total number of atoms of the element present in the molecule of a substance. It confirms the type of atoms as well the number of atoms of the same type present in the molecule. For example, the molecular formula of water is ${\text{H}}_{\text{2}}\text{O}$ ; thus, it can be seen that 1 water molecule contains 2 hydrogen atoms and 1 oxygen atom.

Thus, the molecular formula gives information about the total number of atoms of different elements present in the molecule.

The structural formula of a compound shows the arrangement of atoms and the types of bond present in it.

The structural formula explains the location of atoms in a molecule. It also helps in identifying the number and type of chemical bonds present in the molecule. For example, the structural formula of ethane ${\text{C}}_{\text{2}}{\text{H}}_{\text{6}}$ is as follows:

  

From the above structural formula, it can be identified that two carbon atoms are bonded to each other via a single bond and there are six C-H single bonds present in the compound.

Thus, the number of atoms present in a compound can be identified from its molecular formula but to understand the location of atoms, the structural formula is required.