Question

How many moles of oxygen are in 8.25g of O?

Answer 1

8.25 grams of O2 has 0.258 moles of Oxygen. Here's how you figure that out:
Oxygen is one of the 7 diatomic elements, so it is normally O2.
You find it's molar mass (or mass for one mole of it) by adding up two of the masses from the Periodic Table.

Answer 2

Answer: 0.531 mole

Step-by-step explanation:

I mole of Oxygen = 16g

Let x = 8.25g of Oxygen

Hence,

x = (8.25 * 1) / 16 mole

x = 0.531 mole

Therefore, there is 0.531 mole of Oxygen in 8.25g of Oxygen