A sample contains $12.046 \times 10^{23}$ atoms of iron. How many moles of iron does it contain?

1. Number of moles $= \dfrac{\text{number of atoms}}{N_A}$. 2. $= \dfrac{12.046 \times 10^{23}}{6.023 \times 10^{23}}$. 3. $= 2$ moles of iron. Note that $12.046$ is exactly twice $6.023$, so the answer is 2, not 0.5. _Source: Samacheer Kalvi (TN SCERT) Class 10 Science, Unit 7 Atoms and Molecules "Solved Problems", p.106_