Question

The amount of oxygen in $3.6$ moles of water is :

• A. 115.2 g
• B. 57.6 g
• C. 28.8 g
• D. 18.4 g

Answer 1

The Correct Option is B

To determine the amount of oxygen in 3.6 moles of water, we need to perform the following calculations:

1. Identify the chemical composition of water, which is H₂O, consisting of 2 hydrogen atoms and 1 oxygen atom.
2. The molar mass of water is calculated as: 2 \times 1 \text{ g/mol (for hydrogen)} + 16 \text{ g/mol (for oxygen)} = 18 \text{ g/mol}.
3. Given that we have water, we need to specifically find out how much of it is oxygen by weight. The weight of the oxygen in 18 g of water is 16 g (since oxygen is responsible for 16 of the 18 total grams of a mole of water).
4. Calculate the mass of oxygen in 3.6 moles of water:
   • Mass of water in 3.6 moles = 3.6 \times 18 \text{ g} = 64.8 \text{ g}.
   • Calculate oxygen's share: Since 16 g out of 18 g is oxygen, the mass of oxygen in 3.6 moles of water is calculated by:
     Oxygen mass fraction = \frac{16}{18}
     Total oxygen mass = \left(\frac{16}{18}\right) \times 64.8 = 57.6 \text{ g}.
5. Therefore, the amount of oxygen in 3.6 moles of water is 57.6 g, which matches the option 57.6 g.

Conclusion: The correct answer is 57.6 g, which accurately represents the oxygen content in 3.6 moles of water.