Answer:
127.57 moles
Step-by-step explanation:
To find the number of moles in a substance given it's number of entities we use the formula
![n = (N)/(L) \\](https://img.qammunity.org/2021/formulas/chemistry/high-school/ak7k0w4ze80j1ablopkgu8j8wur48jz22k.png)
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
![n = \frac{7.68 * {10}^(25) }{6.02 * {10}^(23) } \\ = 127.574750...](https://img.qammunity.org/2021/formulas/chemistry/college/6mbzvga9tpsmhe21362920s4ozetmwnfit.png)
We have the final answer as
127.57 moles
Hope this helps you