Chapter 10, Problem 159A

Interpretation Introduction

Interpretation:

The given formula needs to be classified as empirical formula or molecular formula.

${\text{NO, N}}_{\text{2}}{\text{O, NO}}_{\text{2}}{\text{, N}}_{\text{2}}{\text{O}}_{\text{4}}{\text{, N}}_{\text{2}}{\text{O}}_{\text{5}}$

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 159A

Empirical formula = ${\text{NO, NO}}_{\text{2}}$

Molecular formula = ${\text{NO, N}}_{\text{2}}{\text{O, NO}}_{\text{2}}{\text{, N}}_{\text{2}}{\text{O}}_{\text{4}}{\text{, N}}_{\text{2}}{\text{O}}_{\text{5}}$

Explanation of Solution

Given information:

${\text{NO, N}}_{\text{2}}{\text{O, NO}}_{\text{2}}{\text{, N}}_{\text{2}}{\text{O}}_{\text{4}}{\text{, N}}_{\text{2}}{\text{O}}_{\text{5}}$

Empirical formula is the simplest form of formula which has simple ratio of all bonded atoms. In the given formulae, ${\text{NO, NO}}_{\text{2}}{\text{, N}}_{\text{2}}\text{O}$ must be empirical formula as it has simplest ratio of bonded atoms. All ${\text{N}}_{\text{2}}{\text{O}}_{\text{4}}{\text{, N}}_{\text{2}}{\text{O}}_{\text{5}}$ are molecular formulae as they can be written as simplest ratio of bonded atoms. ${\text{NO, NO}}_{\text{2}}{\text{, N}}_{\text{2}}\text{O}$ are molecular formula also.

Conclusion

Empirical formulae must have simplest ratio of atoms whereas molecular formula can be determined by factor ‘n’ and empirical formula.