Answer:
1.3 x 10²⁴ atoms Fe
Step-by-step explanation:
To convert moles to atoms, you need to multiply your given value by Avogadro's Number. This causes the conversion to occur because Avogadro's Number exists as a ratio. It is the ratio that allows for the cancellation of units during multiplication. This is why atoms should be in the numerator of your conversion. The final answer should have 2 sig figs to reflect the given value.
Avogadro's Number:
1 mole = 6.022 x 10²³ atoms
2.1 moles Fe 6.022 x 10²³ atoms
--------------------- x ------------------------------- = 1.3 x 10²⁴ atoms Fe
1 mole