Chapter 10, Problem 143A

Interpretation Introduction

Interpretation:

The mass of iron(III) chloride contains $2.35\times {10}^{23}$ chlorine ions 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 143A

Mass of iron(III) chloride contains $2.35\times {10}^{23}$ chlorine ions = 21.1 g

Explanation of Solution

The given compound is iron(III) chloride.

Molecular formula = ${\text{FeCl}}_{\text{3}}$

Number of chloride ions = $2.35\times {10}^{23}$

The molar mass of ${\text{FeCl}}_{\text{3}}$ = $\text{1}\left(55.85\text{ g/mole}\right)+3\left(35.45\text{ g/mole}\right)$

= $162.2\text{ g/mole}$

${\text{FeCl}}_{\text{3}}$ contains one mole of iron and three moles of chlorine.

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

Thus, the mass of ${\text{FeCl}}_{\text{3}}$ = $\frac{1\text{ mole}}{6.022\times {10}^{23}\text{ ions}}\times 162.2\text{ g/mole}\times \frac{2.35\times {10}^{23}\text{ ions}}{3\text{ mole}}$

= 21.1 g

Mass of iron(III) chloride contains $2.35\times {10}^{23}$ chlorine ions = 21.1 g