Which of the following gas samples would have the largest number of representative particles at standard temperature and pressure (STP)?

• A. 11.2 L of N2
• B. 5.60 L of CO2
• C. 16.8 L of He
• D. 22.4 L of O2

Answer: (D)

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 means that the volume of a gas sample at STP is directly proportional to the number of moles, and thus to the number of representative particles (atoms or molecules).
2. Calculate the number of moles for each gas sample using the formula: \(\text{moles} = \frac{\text{volume at STP}}{22.4\, \text{L/mol}}\). For example, for 11.2 L of N\_2, the moles would be \(\frac{11.2}{22.4}\).
3. Repeat the calculation for 5.60 L of CO\_2 and 16.8 L of He using the same formula to find their respective moles.
4. Compare the calculated moles for each gas sample. The gas with the largest volume at STP will have the largest number of moles and therefore the largest number of representative particles.
5. Confirm that 22.4 L of O\_2 corresponds to exactly 1 mole of gas, which is greater than the moles calculated for the other volumes, indicating it has the largest number of representative particles.