Question

Which one of the following has the same number of atoms as are in 6g of H₂O

• A. 0.4G He
• B. 22g CO₂
• C. 1g H₂
• D. 12g CO

Answer 1

The Correct Option is C

To solve the problem, we need to find which option contains the same number of atoms as 6 g of H₂O.

1. Calculate Moles of H₂O:
Molar mass of water (H₂O) = 18 g/mol
Moles of water = $ \frac{6}{18} = 0.333 \, \text{mol} $

2. Calculate Number of Atoms in H₂O:
Each molecule of water contains 3 atoms (2 Hydrogen + 1 Oxygen).
So, total atoms = $0.333 \times 6.022 \times 10^{23} \times 3$
= $6.022 \times 10^{23} \times 1 = 6.022 \times 10^{23}$ atoms

3. Find Which Option Has the Same Number of Atoms:

• 1 g H₂: Molar mass = 2 g/mol
  Moles = $ \frac{1}{2} = 0.5 $ mol
  Each H₂ molecule has 2 atoms
  Atoms = $0.5 \times 6.022 \times 10^{23} \times 2 = 6.022 \times 10^{23}$
• 0.4 g He: Molar mass = 4 g/mol → 0.1 mol → $0.1 \times 6.022 \times 10^{23}$ = fewer atoms
• 22 g CO₂: Molar mass = 44 g/mol → 0.5 mol
  Each CO₂ has 3 atoms → $0.5 \times 3 \times 6.022 \times 10^{23}$ = $9.033 \times 10^{23}$ atoms
• 12 g CO: Molar mass = 28 g/mol → $ \frac{12}{28} \approx 0.43 $ mol
  Each CO has 2 atoms → $0.43 \times 2 \times 6.022 \times 10^{23} \approx 5.2 \times 10^{23}$ atoms

Final Answer:
The option with the same number of atoms as in 6 g of water is 1 g H₂.