Chapter 10.4, Problem 72SSC

Interpretation Introduction

Interpretation:

The relation between molecular and empirical formula needs to be determined, if the molar mass of the compound is twice that of its empirical formula.

Concept introduction:

Empirical formula is the simplest formula of any organic or inorganic compound that represents the simple ratio of all atoms present in the molecule. It can be calculated with the help of elemental composition of molecule. Certain steps must be used to get the empirical formula:

• Consider mass % as mass in grams and calculate moles of element with the help of molar mass
• Calculate the moles of each element in least whole number
• Write the number of each atom as subscript to write the empirical formula.

Answer to Problem 72SSC

The molecular formula must contain twice of the atoms as in the empirical formula.

Explanation of Solution

If the molar mass of compound is twice of the mass of empirical formula, it means the value of n must be 2.

$\text{n = }\frac{\text{molar mass}}{\text{mass of empirical formula}}$

Since the molecular formula and empirical formula are related with each other through ‘n’ value so:

$\text{Molecular formula = (empirical formula) }\times \text{ n }$

So the molecular formula must contain twice of the atoms as in the empirical formula.

Conclusion

The molecular formula must contain twice of the atoms as in the empirical formula.