Answer:
19.948 mol.
Step-by-step explanation:
- Knowing that every one mole of a substance contains Avogadro's no. of molecules (NA = 6.022 x 10²³).
Using cross multiplication:
1.0 mole → 6.022 x 10²³ atoms of He.
??? mole → 12.013 x 10²⁴ atoms of He.
∴ The no. of moles of are in 12.013 x 10²⁴ atoms of He = (12.013 x 10²⁴ atoms of He) (1.0 mole) / (6.022 x 10²³ atoms of He) = 19.948 mol.