Chapter 3, Problem 3.30P

(a)

Interpretation Introduction

Interpretation: Empirical formula of compound that has $0.039\text{ mol Fe}$ and $\text{0}\text{.052 mol O}$ should be determined.

Concept introduction:An empirical formula depicts the ratio of simplified whole-number of atoms contained in a molecule. The molecular formula depicts exact number of each atom found in a molecule.

The steps to determine empirical formula are stated as follows:

Divide mass of element by its molar mass to convert mass to moles as follows:

  $\text{Amount}\left(\text{mol}\right)=\left(\text{Given mass}\left(\text{g}\right)\right)\left(\frac{1\text{ mol}}{\text{No}\text{. of grams}}\right)$

Number of moles thus calculated is written as subscript of element’s symbol and this results in a preliminary empirical formula.

In order to convert the moles to the whole number subscripts, each subscript is divided by the smallest subscript. Finally, empirical formula can be simply written from the molar ratio of each element specified at the superscript of each symbol present in the compound.

(b)

Interpretation Introduction

Interpretation: Empirical formula of compound that has $\text{0}\text{.903 g P}$ and $\text{6}\text{.99 g Br}$ should be determined.

Concept introduction:An empirical formula depicts the ratio of simplified whole-number of atoms contained in a molecule. The molecular formula depicts exact number of each atom found in a molecule.

The steps to determine empirical formula are stated as follows:

Divide mass of element by its molar mass to convert mass to moles as follows:

  $\text{Amount}\left(\text{mol}\right)=\left(\text{Given mass}\left(\text{g}\right)\right)\left(\frac{1\text{ mol}}{\text{No}\text{. of grams}}\right)$

Number of moles thus calculated is written as subscript of element’s symbol and this results in a preliminary empirical formula.

In order to convert the moles to the whole number subscripts, each subscript is divided by the smallest subscript. Finally, empirical formula can be simply written from the molar ratio of each element specified at the superscript of each symbol present in the compound.

(c)

Interpretation Introduction

Interpretation: Empirical formula of the compound that has $\text{79}\text{.9 \% C}$ should be determined.

Concept introduction:An empirical formula depicts the ratio of simplified whole-number of atoms contained in a molecule. The molecular formula depicts exact number of each atom found in a molecule.

The steps to determine empirical formula are stated as follows:

Divide mass of element by its molar mass to convert mass to moles as follows:

  $\text{Amount}\left(\text{mol}\right)=\left(\text{Given mass}\left(\text{g}\right)\right)\left(\frac{1\text{ mol}}{\text{No}\text{. of grams}}\right)$

Number of moles thus calculated is written as subscript of element’s symbol and this results in a preliminary empirical formula.

In order to convert the moles to the whole number subscripts, each subscript is divided by the smallest subscript. Finally, empirical formula can be simply written from the molar ratio of each element specified at the superscript of each symbol present in the compound.