What is the volume, in liters, of 7.25 g of oxygen gas (O_2) at standard temperature and pressure (STP)?

• A. 11.2 L
• B. 5.07 L
• C. 7.25 L
• D. 2.80 L

Answer: (B)

Verified step by step guidance

1. Identify the given information: mass of oxygen gas (O\_2) is 7.25 g, and the conditions are at standard temperature and pressure (STP).
2. Recall that at STP, 1 mole of any ideal gas occupies 22.4 liters. This is a key conversion factor for volume and moles of gas.
3. Calculate the molar mass of oxygen gas (O\_2). Since each oxygen atom has an atomic mass of approximately 16.00 g/mol, the molar mass of O\_2 is 2 \times 16.00 g/mol = 32.00 g/mol.
4. Convert the given mass of oxygen gas to moles using the formula: \(\text{moles} = \frac{\text{mass}}{\text{molar mass}} = \frac{7.25\ \text{g}}{32.00\ \text{g/mol}}\).
5. Use the molar volume at STP to find the volume: \(\text{volume} = \text{moles} \times 22.4\ \text{L/mol}\). Substitute the moles calculated in the previous step to get the volume in liters.