The number of atoms in 7.4 moles of iron are

1 Mole iron has ${\text{6.023×10}}^{23}\text{ atoms}$  of Fe.

Number of atoms present in 7.4 mol of iron is

$\frac{6.022\times {10}^{23}\text{\hspace{0.17em}atoms}}{1\text{\hspace{0.17em}mol\hspace{0.17em}Fe}}\times 7.4\text{\hspace{0.17em}mol\hspace{0.17em}Fe\hspace{0.17em}\hspace{0.17em}=\hspace{0.17em}44.5}\times {\text{10}}^{\text{23}}$