Answer : [tex]0.34\times 10^{23}atoms[/tex]
Explanation : Given,
Mass of [tex]Fe_2O_3[/tex] = 4.5 g
Molar mass of [tex]Fe_2O_3[/tex] = 159.69 g/mole
Molar mass of Fe = 56 g/mole
First we have to calculate the moles of [tex]Fe_2O_3[/tex].
[tex]\text{Moles of }Fe_2O_3=\frac{\text{Mass of }Fe_2O_3}{\text{Molar mass of }Fe_2O_3}=\frac{4.5g}{159.69g/mole}=0.028moles[/tex]
Now we have to calculate the moles of Fe.
The balanced chemical reaction will be,
[tex]Fe_2O_3+3Mg\rightarrow 2Fe+3MgO[/tex]
From the balanced reaction we conclude that
As, 1 moles of [tex]Fe_2O_3[/tex] react to give 2 moles of [tex]Fe[/tex]
So, 0.028 moles of [tex]Fe_2O_3[/tex] react with [tex]\frac{2}{1}\times 0.028=0.056[/tex] moles of [tex]Fe[/tex]
Now we have to calculate the mass of Fe.
[tex]\text{Atoms of}Fe=\text{Moles of }Fe\times \text{Avogadro's Number}[/tex]
[tex]\text{Atoms of}Fe=(0.056mole)\times (6.023\times 10^{23})=0.34\times 10^{23}atoms[/tex]
Therefore, the number of atoms will be [tex]0.34\times 10^{23}atoms[/tex]
