Question

Which has maximum number of oxygen atoms?

• A. 1gmofO
• B. 1gmofO₂
• C. 1gmofO₃
• D. All have same no. of O-atoms

Answer 1

Answer: (D)

All have same no. of O-atoms

Answer 2

To determine which option has the maximum number of oxygen atoms, we need to calculate the number of oxygen atoms present in 1 gram of each species.

Let $N_A$ be Avogadro's number ($6.022 \times 10^{23}$). The atomic mass of oxygen (O) is approximately 16 g/mol.

(A) 1 gm of O (atomic oxygen):
The species is atomic oxygen (O).
Molar mass of O = 16 g/mol.
Number of moles of O in 1 gm = $\frac{\text{Mass}}{\text{Molar mass}} = \frac{1 \text{ gm}}{16 \text{ g/mol}} = \frac{1}{16}$ mol.
Number of oxygen atoms = Number of moles $\times N_A = \frac{1}{16} \times N_A$ atoms.

(B) 1 gm of O₂ (molecular oxygen):
The species is molecular oxygen (O₂).
Molar mass of O₂ = $2 \times \text{Atomic mass of O} = 2 \times 16 \text{ g/mol} = 32 \text{ g/mol}$.
Number of moles of O₂ in 1 gm = $\frac{\text{Mass}}{\text{Molar mass}} = \frac{1 \text{ gm}}{32 \text{ g/mol}} = \frac{1}{32}$ mol.
Each O₂ molecule contains 2 oxygen atoms.
Number of oxygen atoms = Number of moles of O₂ $\times N_A \times 2 = \frac{1}{32} \times N_A \times 2 = \frac{2}{32} \times N_A = \frac{1}{16} \times N_A$ atoms.

(C) 1 gm of O₃ (ozone):
The species is ozone (O₃).
Molar mass of O₃ = $3 \times \text{Atomic mass of O} = 3 \times 16 \text{ g/mol} = 48 \text{ g/mol}$.
Number of moles of O₃ in 1 gm = $\frac{\text{Mass}}{\text{Molar mass}} = \frac{1 \text{ gm}}{48 \text{ g/mol}} = \frac{1}{48}$ mol.
Each O₃ molecule contains 3 oxygen atoms.
Number of oxygen atoms = Number of moles of O₃ $\times N_A \times 3 = \frac{1}{48} \times N_A \times 3 = \frac{3}{48} \times N_A = \frac{1}{16} \times N_A$ atoms.

Comparing the number of oxygen atoms in each case: (A) 1 gm of O: $\frac{1}{16} N_A$ atoms (B) 1 gm of O₂: $\frac{1}{16} N_A$ atoms (C) 1 gm of O₃: $\frac{1}{16} N_A$ atoms

All three options contain the same number of oxygen atoms. Therefore, the option stating that all have the same number of O-atoms is correct.