Answer :
To find the volume occupied by 8.00 g of oxygen gas (O₂) at standard temperature and pressure (STP), we can use the properties of gases at STP and the concept of molar mass.
1. Determine the molar mass of oxygen (O₂):
- Oxygen (O) has an atomic mass of approximately 16.00 g/mol. Since O₂ is a diatomic molecule, its molar mass is 16.00 g/mol × 2 = 32.00 g/mol.
2. Calculate the number of moles of O₂:
- Use the formula:
[tex]\[
\text{Number of moles} = \frac{\text{mass}}{\text{molar mass}}
\][/tex]
- Plug in the values:
[tex]\[
\text{Number of moles of O₂} = \frac{8.00 \text{ g}}{32.00 \text{ g/mol}} = 0.25 \text{ moles}
\][/tex]
3. Determine the volume occupied by the gas at STP:
- At STP, one mole of a gas occupies 22.4 liters.
- Therefore, for the number of moles we have:
[tex]\[
\text{Volume} = \text{moles} \times \text{molar volume at STP}
\][/tex]
- Substitute the known values:
[tex]\[
\text{Volume} = 0.25 \text{ moles} \times 22.4 \text{ L/mole} = 5.60 \text{ L}
\][/tex]
Thus, the volume occupied by 8.00 g of oxygen gas at STP is 5.60 L. The correct answer is option A) 5.60 L.
1. Determine the molar mass of oxygen (O₂):
- Oxygen (O) has an atomic mass of approximately 16.00 g/mol. Since O₂ is a diatomic molecule, its molar mass is 16.00 g/mol × 2 = 32.00 g/mol.
2. Calculate the number of moles of O₂:
- Use the formula:
[tex]\[
\text{Number of moles} = \frac{\text{mass}}{\text{molar mass}}
\][/tex]
- Plug in the values:
[tex]\[
\text{Number of moles of O₂} = \frac{8.00 \text{ g}}{32.00 \text{ g/mol}} = 0.25 \text{ moles}
\][/tex]
3. Determine the volume occupied by the gas at STP:
- At STP, one mole of a gas occupies 22.4 liters.
- Therefore, for the number of moles we have:
[tex]\[
\text{Volume} = \text{moles} \times \text{molar volume at STP}
\][/tex]
- Substitute the known values:
[tex]\[
\text{Volume} = 0.25 \text{ moles} \times 22.4 \text{ L/mole} = 5.60 \text{ L}
\][/tex]
Thus, the volume occupied by 8.00 g of oxygen gas at STP is 5.60 L. The correct answer is option A) 5.60 L.
