Question

What is the number of moles of oxygen atoms in 4.0 g of \( \text{O}_2 \)?

• A. \( 0.125 \, \text{mol} \)
• B. \( 0.25 \, \text{mol} \)
• C. \( 0.5 \, \text{mol} \)
• D. \( 0.1 \, \text{mol} \)

Hint:

To find the number of moles of atoms in a molecular compound, multiply the moles of the compound by the number of atoms per molecule.

Answer 1

The Correct Option is A

First, calculate the number of moles of \( \text{O}_2 \) in 4.0 g of \( \text{O}_2 \). The molar mass of \( \text{O}_2 \) is: \[ \text{Molar mass of } \text{O}_2 = 32 \, \text{g/mol} \] Now, calculate the moles of \( \text{O}_2 \): \[ \text{Moles of } \text{O}_2 = \frac{\text{Mass of } \text{O}_2}{\text{Molar mass of } \text{O}_2} = \frac{4.0 \, \text{g}}{32 \, \text{g/mol}} = 0.125 \, \text{mol} \] Since each molecule of \( \text{O}_2 \) contains 2 oxygen atoms, the number of moles of oxygen atoms will be: \[ \text{Moles of oxygen atoms} = 2 \times 0.125 \, \text{mol} = 0.25 \, \text{mol} \] Thus, the number of moles of oxygen atoms in 4.0 g of \( \text{O}_2 \) is \( 0.25 \, \text{mol} \).