Answer:
5.35×10²⁴ atoms of Li
Explanation:
To solve this we apply this rule of three:
We know that 1 mol contains 6.02×10²³ atoms
Therefore, 8.9 moles must contain (8.9 . 6.02×10²³) / 1 = 5.35×10²⁴ atoms
One mol is the amount of substance containing as many elemental entities as atoms, which are contained in 12 g of the C¹² isotope
In conclussion 6.02×10²³ atoms of C¹² isotope weighs 12 g