Chapter 10, Problem 129A

Interpretation Introduction

Interpretation:

The number of molecules of carbon tetrachloride present in 3.00 mole of ${\text{CCl}}_4$ should be calculated. The number of carbon atoms, chlorine atoms and the total number of atoms present in ${\text{CCl}}_4$ should be calculated.

Concept introduction:

The number of moles of a compound is defined as the ratio of the given mass of the compound to the molar or molecular mass of the compound.

The mathematical expression is given by:

Number of moles = $\frac{\text{given mass of the compound}}{\text{molar mass of the compound}}$

The one mole of any substance is equal to the Avogadro number, i.e., $6.022\times {10}^{23}$ atoms.

Answer to Problem 129A

Number of molecules of carbon tetrachloride present in 3.00 mole of ${\text{CCl}}_4$ = $18.066\times {\text{10}}^{23}\text{ atoms}$

Number of carbon atoms = $18.066\times {\text{10}}^{23}\text{ atoms}$

Number of chlorine atoms = $72.264\times {10}^{23}\text{ atoms}$

Total number of atoms = $9.033\times {10}^{24}\text{ atoms}$

Explanation of Solution

Number of moles of ${\text{CCl}}_4$ = 3.00 mole

Since one mole of any substance is equal to the Avogadro number, i.e., $6.022\times {10}^{23}$ atoms.

Number of moles = $\text{number of molecules ×}\frac{1\text{ mole}}{6.022\times 10\text{molecules}}$

Put the values,

$\text{3}\text{.00 mole}$ = $\text{number of molecules ×}\frac{1\text{ mole}}{6.022\times 10\text{molecules}}$

$\text{Number of molecules }=\text{3}\text{.00 mole}\times 6.022\times {10}^{23}\frac{\text{molecules}}{\text{mole}}$

Number of molecules of ${\text{CCl}}_4$ = $18.066\times {\text{10}}^{23}\text{ molecules}$

In ${\text{CCl}}_4$, one atom of carbon and four atoms of chlorine are present.

Thus, number of carbon atoms in ${\text{CCl}}_4$ = $18.066\times {\text{10}}^{23}\text{ atoms}$

Number of chlorine atoms in ${\text{CCl}}_4$ = $18.066\times {\text{10}}^{23}\text{ atoms}\times 4$

= $72.264\times {10}^{23}\text{ atoms}$

Total number of atoms in ${\text{CCl}}_4$ = $72.264\times {10}^{23}\text{ atoms +}18.066\times {\text{10}}^{23}\text{ atoms}$

= $9.033\times {10}^{24}\text{ atoms}$