At standard temperature and pressure (STP), how many moles of nitrogen gas (N_2) are present in a 3.50 L sample?

• A. 0.156 mol
• B. 0.467 mol
• C. 0.312 mol
• D. 0.224 mol

Answer: (A)

Verified step by step guidance

1. Recall that at standard temperature and pressure (STP), one mole of any ideal gas occupies 22.4 liters. This is a key concept from the ideal gas law and molar volume of gases.
2. Identify the given volume of nitrogen gas, which is 3.50 L, and the molar volume at STP, which is 22.4 L/mol.
3. Set up the relationship to find moles using the formula: \(\text{moles} = \frac{\text{volume of gas}}{\text{molar volume at STP}}\).
4. Substitute the known values into the formula: \(\text{moles} = \frac{3.50\, \text{L}}{22.4\, \text{L/mol}}\).
5. Perform the division to calculate the number of moles of nitrogen gas present in the 3.50 L sample at STP.