2g of oxygen contains number of atoms equal to that in

Options

A. 0.5 g of hydrogen
B. 4g of sulphur
C. 7 g of nitrogen
D. 2.3 g of sodium

Explanation

To solve the problem of how many atoms are present in 2 g of oxygen compared to other substances, we will follow these steps:

### Step 1: Calculate the number of moles of Oxygen (O2)
- Given mass of O2 = 2 g
- Molar mass of O2 = 32 g/mol (since O has a molar mass of 16 g/mol and O2 has 2 oxygen atoms)

Using the formula for moles:
\[ \text{Number of moles of O2} = \frac{\text{Given mass}}{\text{Molar mass}} = \frac{2 \text{ g}}{32 \text{ g/mol}} = 0.0625 \text{ moles} \]

### Step 2: Calculate the number of atoms in O2
- Each molecule of O2 contains 2 atoms of oxygen.
- Therefore, the number of atoms in 2 g of O2 is:
\[ \text{Number of atoms} = \text{Number of moles} \times \text{Avogadro's number} \times 2 \]
\[ = 0.0625 \text{ moles} \times 6.022 \times 10^{23} \text{ atoms/mole} \times 2 \]
\[ = 0.0625 \times 6.022 \times 10^{23} \times 2 = 7.5 \times 10^{22} \text{ atoms} \]

### Step 3: Calculate the number of atoms in 0.5 g of Hydrogen (H2)
- Given mass of H2 = 0.5 g
- Molar mass of H2 = 2 g/mol

Calculating moles:
\[ \text{Number of moles of H2} = \frac{0.5 \text{ g}}{2 \text{ g/mol}} = 0.25 \text{ moles} \]

Calculating atoms:
\[ \text{Number of atoms} = 0.25 \text{ moles} \times 6.022 \times 10^{23} \text{ atoms/mole} \times 2 = 3.01 \times 10^{23} \text{ atoms} \]

### Step 4: Calculate the number of atoms in 4 g of Sulfur (S)
- Given mass of S = 4 g
- Molar mass of S = 32 g/mol

Calculating moles:
\[ \text{Number of moles of S} = \frac{4 \text{ g}}{32 \text{ g/mol}} = 0.125 \text{ moles} \]

Calculating atoms:
\[ \text{Number of atoms} = 0.125 \text{ moles} \times 6.022 \times 10^{23} \text{ atoms/mole} = 7.5 \times 10^{22} \text{ atoms} \]

### Step 5: Calculate the number of atoms in 7 g of Nitrogen (N2)
- Given mass of N2 = 7 g
- Molar mass of N2 = 28 g/mol

Calculating moles:
\[ \text{Number of moles of N2} = \frac{7 \text{ g}}{28 \text{ g/mol}} = 0.25 \text{ moles} \]

Calculating atoms:
\[ \text{Number of atoms} = 0.25 \text{ moles} \times 6.022 \times 10^{23} \text{ atoms/mole} \times 2 = 3.01 \times 10^{23} \text{ atoms} \]

### Step 6: Calculate the number of atoms in 2.3 g of Sodium (Na)
- Given mass of Na = 2.3 g
- Molar mass of Na = 23 g/mol

Calculating moles:
\[ \text{Number of moles of Na} = \frac{2.3 \text{ g}}{23 \text{ g/mol}} = 0.1 \text{ moles} \]

Calculating atoms:
\[ \text{Number of atoms} = 0.1 \text{ moles} \times 6.022 \times 10^{23} \text{ atoms/mole} = 6.022 \times 10^{22} \text{ atoms} \]

### Conclusion
From the calculations, we find:
- 2 g of O2 contains \( 7.5 \times 10^{22} \) atoms.
- 0.5 g of H2 contains \( 3.01 \times 10^{23} \) atoms.
- 4 g of S contains \( 7.5 \times 10^{22} \) atoms.
- 7 g of N2 contains \( 3.01 \times 10^{23} \) atoms.
- 2.3 g of Na contains \( 6.022 \times 10^{22} \) atoms.

Thus, the number of atoms in 2 g of oxygen is equal to that in 4 g of sulfur.