2 g of oxygen contain same number of atoms as contained by

Options

A. `0.5` g hydrogen
B. `4.0` g sulphur
C. `7.0` g nitrogen
D. `2.3` g sodium

Explanation

To find out which substance contains the same number of atoms as 2 grams of oxygen, we will follow these steps:

### Step 1: Determine the number of atoms in 2 grams of oxygen (O2).
1. **Understand the molar mass of oxygen**: The molar mass of oxygen (O) is 16 grams per mole.
2. **Calculate the number of moles in 2 grams of oxygen**:
\[ \text{Number of moles} = \frac{\text{mass}}{\text{molar mass}} = \frac{2 \text{ g}}{16 \text{ g/mol}} = 0.125 \text{ moles} \]
3. **Use Avogadro's number to find the number of atoms**:
\[ \text{Number of atoms} = \text{Number of moles} \times \text{Avogadro's number} = 0.125 \text{ moles} \times 6.022 \times 10^{23} \text{ atoms/mole} \]
\[ \text{Number of atoms} = 7.5 \times 10^{22} \text{ atoms} \]

### Step 2: Compare with other substances to find the equivalent number of atoms.
1. **Hydrogen (H)**:
- Molar mass of H = 1 g/mol
- For 0.5 g of H:
\[ \text{Number of moles} = \frac{0.5 \text{ g}}{1 \text{ g/mol}} = 0.5 \text{ moles} \]
\[ \text{Number of atoms} = 0.5 \text{ moles} \times 6.022 \times 10^{23} \text{ atoms/mole} = 3.011 \times 10^{23} \text{ atoms} \]

2. **Sulfur (S)**:
- Molar mass of S = 32 g/mol
- For 4 g of S:
\[ \text{Number of moles} = \frac{4 \text{ g}}{32 \text{ g/mol}} = 0.125 \text{ moles} \]
\[ \text{Number of atoms} = 0.125 \text{ moles} \times 6.022 \times 10^{23} \text{ atoms/mole} = 7.5 \times 10^{22} \text{ atoms} \]

3. **Nitrogen (N)**:
- Molar mass of N = 14 g/mol
- For 7 g of N:
\[ \text{Number of moles} = \frac{7 \text{ g}}{14 \text{ g/mol}} = 0.5 \text{ moles} \]
\[ \text{Number of atoms} = 0.5 \text{ moles} \times 6.022 \times 10^{23} \text{ atoms/mole} = 3.011 \times 10^{23} \text{ atoms} \]

### Conclusion:
From the calculations, we find that 2 grams of oxygen contains \(7.5 \times 10^{22}\) atoms, which is the same as the number of atoms in 4 grams of sulfur.

### Final Answer:
**2 g of oxygen contains the same number of atoms as 4 g of sulfur.**

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