Chapter U4.77, Problem 7E

Interpretation Introduction

Interpretation:

The mass of 5 mole of iron (III) oxide ( ${\text{Fe}}_{\text{2}}{\text{O}}_{\text{3}}$ ) should be calculated.

Concept Introduction:

Mole is SI unit which is used to measure the quantity of the substance. It is the quantity of a substance which contains same number of atoms as present in accurately 12.00 g of carbon-12 is known as mole

Number of moles is defined as the ratio of mass to the molar mass.

  $\text{Number of moles = }\frac{\text{Mass (g)}}{\text{Molar mass}}$

The ratio of mass of the given compound to the number of moles of compound is known as molar mass.

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

Answer to Problem 7E

Mass of iron (III) oxide ( ${\text{Fe}}_{\text{2}}{\text{O}}_{\text{3}}$ ) = $798.5\text{ g}$ .

Explanation of Solution

The given molecule is iron (III) oxide ( ${\text{Fe}}_{\text{2}}{\text{O}}_{\text{3}}$ ).

Number of moles of ${\text{Fe}}_{\text{2}}{\text{O}}_{\text{3}}$ = 5 mole.

Molar mass of ${\text{Fe}}_{\text{2}}{\text{O}}_{\text{3}}$ = $\text{2}\times \text{55}\text{.845 g/mole + 3}\times \text{16 g/mole}$

= $159.7\text{ g/mole}$

  $\text{Number of moles = }\frac{\text{Mass (g)}}{\text{Molar mass}}$

Put the values,

  $\text{5 mole = }\frac{\text{Mass (g)}}{159.7\text{ g/mole}}$

Mass of ${\text{Fe}}_{\text{2}}{\text{O}}_{\text{3}}$ = $798.5\text{ g}$

Therefore, mass of iron (III) oxide ( ${\text{Fe}}_{\text{2}}{\text{O}}_{\text{3}}$ ) = $798.5\text{ g}$