What is the density of oxygen gas (O_2) at standard temperature and pressure (STP)?

• A. 32.0 g/L
• B. 1.43 g/L
• C. 0.89 g/L
• D. 22.4 g/L

Answer: (B)

Verified step by step guidance

1. Recall that the density (\(d\)) of a gas can be calculated using the formula \(d = \frac{m}{V}\), where \(m\) is the mass of the gas and \(V\) is its volume.
2. At standard temperature and pressure (STP), one mole of any ideal gas occupies a volume of 22.4 liters. This is a key fact to use in the calculation.
3. Determine the molar mass of oxygen gas (\(O_2\)). Since each oxygen atom has an atomic mass of approximately 16.0 g/mol, the molar mass of \(O_2\) is \$2 \times 16.0 = 32.0$ g/mol.
4. Use the molar mass as the mass (\(m\)) of one mole of oxygen gas and the molar volume at STP (22.4 L) as the volume (\(V\)) to calculate the density: \(d = \frac{32.0 \text{ g}}{22.4 \text{ L}}\).
5. Perform the division to find the density in g/L, which will give you the density of oxygen gas at STP.