Which has the highest number of oxygen atoms?
`1gO_(2) or 1gO_(3) or 1gO`

Options

A. `1gO_(2)`
B. `1gO_(3)`
C. `1gO`
D. All have same atoms

Answer

To determine which of the given substances has the highest number of oxygen atoms in 1 gram, we will analyze each substance: \( O_2 \) (oxygen gas), \( O_3 \) (ozone), and \( O \) (atomic oxygen).

### Step-by-step Solution:

1. **Calculate the number of moles for \( O_2 \):**
- The molar mass of \( O_2 \) is \( 16 \, \text{g/mol} \times 2 = 32 \, \text{g/mol} \).
- Number of moles in 1 gram of \( O_2 \):
\[ \text{Number of moles} = \frac{\text{mass}}{\text{molar mass}} = \frac{1 \, \text{g}}{32 \, \text{g/mol}} = 0.03125 \, \text{mol} \]

2. **Calculate the number of oxygen atoms in \( O_2 \):**
- Each molecule of \( O_2 \) contains 2 oxygen atoms.
- Therefore, the number of oxygen atoms in 1 gram of \( O_2 \):
\[ \text{Number of atoms} = 0.03125 \, \text{mol} \times 2 \times N_A = 0.0625 \, N_A \]
where \( N_A \) is Avogadro's number (\( 6.022 \times 10^{23} \)).

3. **Calculate the number of moles for \( O_3 \):**
- The molar mass of \( O_3 \) is \( 16 \, \text{g/mol} \times 3 = 48 \, \text{g/mol} \).
- Number of moles in 1 gram of \( O_3 \):
\[ \text{Number of moles} = \frac{1 \, \text{g}}{48 \, \text{g/mol}} = 0.02083 \, \text{mol} \]

4. **Calculate the number of oxygen atoms in \( O_3 \):**
- Each molecule of \( O_3 \) contains 3 oxygen atoms.
- Therefore, the number of oxygen atoms in 1 gram of \( O_3 \):
\[ \text{Number of atoms} = 0.02083 \, \text{mol} \times 3 \times N_A = 0.0625 \, N_A \]

5. **Calculate the number of moles for atomic \( O \):**
- The molar mass of atomic \( O \) is \( 16 \, \text{g/mol} \).
- Number of moles in 1 gram of atomic \( O \):
\[ \text{Number of moles} = \frac{1 \, \text{g}}{16 \, \text{g/mol}} = 0.0625 \, \text{mol} \]

6. **Calculate the number of oxygen atoms in atomic \( O \):**
- Each atom of \( O \) is a single oxygen atom.
- Therefore, the number of oxygen atoms in 1 gram of atomic \( O \):
\[ \text{Number of atoms} = 0.0625 \, \text{mol} \times N_A = 0.0625 \, N_A \]

### Conclusion:
- For \( O_2 \): \( 0.0625 \, N_A \) oxygen atoms.
- For \( O_3 \): \( 0.0625 \, N_A \) oxygen atoms.
- For atomic \( O \): \( 0.0625 \, N_A \) oxygen atoms.

Thus, all three substances contain the same number of oxygen atoms in 1 gram.

### Final Answer:
All three substances \( O_2 \), \( O_3 \), and \( O \) have the same number of oxygen atoms in 1 gram.