A sample of NO_2 occupies 16.0 L at STP. How many moles of NO_2 are present in the sample?

• A. 0.714 mol
• B. 2.24 mol
• C. 0.500 mol
• D. 1.00 mol

Answer: (A)

Verified step by step guidance

1. Identify the conditions given: the volume of NO_2 gas is 16.0 L at STP (Standard Temperature and Pressure). STP means the temperature is 0°C (273.15 K) and pressure is 1 atm.
2. Recall the molar volume of an ideal gas at STP, which is the volume occupied by 1 mole of any ideal gas under these conditions. This value is 22.4 L/mol.
3. Use the relationship between volume and moles at STP: \(n = \frac{V}{V_m}\), where \(n\) is the number of moles, \(V\) is the volume of the gas, and \(V_m\) is the molar volume at STP (22.4 L/mol).
4. Substitute the given volume and molar volume into the formula: \(n = \frac{16.0\, \text{L}}{22.4\, \text{L/mol}}\).
5. Calculate the quotient to find the number of moles of NO_2 in the sample.